The Circulars for SGR 1935+2154. However, many of the Circulars started with the assumption it was a GRB. ////////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 25975 SUBJECT: Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154 DATE: 19/10/07 18:37:12 GMT FROM: Joshua Wood at MSFC/Fermi-GBM J.Wood (NASA/MSFC) and E. Bissaldi (Politecnico & INFN Bari) report on behalf of the Fermi GBM Team: "At 09:00:53.70 UT on 4 October 2019, the Fermi Gamma-Ray Burst Monitor (GBM) triggered on a bright, SGR-like burst from the direction of the magnetar SGR 1935+2154 (trigger 591872458/191004376). The burst has a duration (T90) of ~0.1 seconds in the energy range 10-300 keV. It is well-fit by a Comptonized model with Epeak 28.71 +/- 2.71 keV and alpha -0.30 +/- 0.55. The event fluence (10-300 keV) from T0-0.112s to T0+0.016s is (7.142 +/- 0.576)E-8 erg/cm^2. The average photon flux in the 10-300 keV band during this period is 14.19 +/- 1.0 ph/s/cm^2. We note that this is the first outburst since June 2016. The analysis results presented above are preliminary. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26151 SUBJECT: GRB 191104A: Fermi GBM Final Real-time Localization DATE: 19/11/04 03:03:53 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 02:53:31 UT on 4 Nov 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191104A (trigger 594528816.391038 / 191104120). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 271.2, Dec = 18.7 (J2000 degrees, equivalent to J2000 18h 04m, 18d 41'), with a statistical uncertainty of 17.5 degrees. The angle from the Fermi LAT boresight is 63.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104120/quicklook/glg_skymap_all_bn191104120.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104120/quicklook/glg_healpix_all_bn191104120.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104120/quicklook/glg_lc_medres34_bn191104120.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26163 SUBJECT: Fermi GBM GRBs 191104 A, B, C and triggers 594534420/191104185 and 594563923/191104527 are not GRBs DATE: 19/11/04 15:41:11 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “On 04 November the Fermi Gamma-ray Burst Monitor triggered on SGR-like bursts from the direction of SGR 1935+2154, tentatively classified as GRBs, which are in fact not due to GRBs: at 01:20:24.06 UT on 4 Nov 2019, trigger 594523229/191104056, at 02:53:31.39 UT on 4 Nov 2019, trigger 594528816/191104120, misclassified as GRB 191104A in GCN 26151, at 04:26:55.87 UT on 4 Nov 2019, trigger 594534420/191104185, at 09:17:53.50 UT on 4 Nov 2019, trigger 594551878/191104387, misclassified as GRB 191104B in GCN 26154, at 10:44:26.31 UT on 4 Nov 2019, trigger 594557071/191104448), misclassified as GRB 191104C in GCN 26157, and at 12:38:38 UT on 04 November 2019, trigger 594563923/191104527" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26153 SUBJECT: Trigger 933083: Swift detection of SGR 1935+2154 DATE: 19/11/04 06:51:17 GMT FROM: Scott Barthelmy at NASA/GSFC E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), A. D'Ai (INAF-IASFPA), V. D'Elia (SSDC), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 06:34:00 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR 1935+2154 (trigger=933083). Swift did not slew to the source. The BAT on-board calculated location is RA, Dec 293.743, +21.896, which is RA(J2000) = 19h 34m 58s Dec(J2000) = +21d 53' 44" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak structure with a duration of about 0.2 sec. The peak count rate was ~4500 counts/sec (15-350 keV), at ~0 sec after the trigger. Swift did not slew to this source because the merit value of the source being observed by Swift was higher than the merit value for this known source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26154 SUBJECT: GRB 191104B: Fermi GBM Final Real-time Localization DATE: 19/11/04 09:28:18 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 09:17:53 UT on 4 Nov 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191104B (trigger 594551878.499554 / 191104387). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 294.3, Dec = 18.9 (J2000 degrees, equivalent to J2000 19h 37m, 18d 53'), with a statistical uncertainty of 6.8 degrees. The angle from the Fermi LAT boresight is 59.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104387/quicklook/glg_skymap_all_bn191104387.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104387/quicklook/glg_healpix_all_bn191104387.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104387/quicklook/glg_lc_medres34_bn191104387.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26160 SUBJECT: GRB 191104B/GRB 191104C are SGR 1935+2154 DATE: 19/11/04 12:35:55 GMT FROM: Jochen Greiner at MPI J.M. Burgess and J. Greiner (both MPE Garching) report: We note that the last two Fermi/GBM triggers (GRB 191104B: Fermi team at MSFC et al., GCN #26154; GRB 191104C: Kunzweiler et al., GCN #26158) were misclassified as GRBs, but due to their short duration, soft spectrum and positional coincidence are likely outbursts from SGR 1935+2154 (which also triggered Swift earlier today (Ambrosi et al., GCN 26153). For the spectral analysis see https://grb.mpe.mpg.de/grb/GRB191104387/ and https://grb.mpe.mpg.de/grb/GRB191104448/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26157 SUBJECT: GRB 191104C: Fermi GBM Final Real-time Localization DATE: 19/11/04 10:54:49 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 10:44:26 UT on 4 Nov 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191104C (trigger 594557071.308326 / 191104448). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 289.4, Dec = 22.7 (J2000 degrees, equivalent to J2000 19h 17m, 22d 41'), with a statistical uncertainty of 2.5 degrees. The angle from the Fermi LAT boresight is 53.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104448/quicklook/glg_skymap_all_bn191104448.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104448/quicklook/glg_healpix_all_bn191104448.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104448/quicklook/glg_lc_medres34_bn191104448.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26158 SUBJECT: GRB 191104C: BALROG localization (Fermi Trigger 594557071 / GRB 191104448) DATE: 19/11/04 11:08:06 GMT FROM: Jochen Greiner at MPE,Garching F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report: The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger 594557071 at 10:44:26 on 04 Nov. 2019 were automatically fitted for spectrum and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427; Berlato et al. 2019, ApJ 873, 60). The best-fit position (1 sigma statistical errors) is: RA(2000.0) = 291.3+/-0.8 deg Decl.(2000.0) = 23.7+/-0.6 deg We estimate an additional systematic error of 2 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB191104448/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB191104448/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB191104448/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26165 SUBJECT: GRB 191104C: Fermi GBM Final Real-time Localization DATE: 19/11/04 20:40:02 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely SHORT GRB At 20:29:39 UT on 4 Nov 2019, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 191104C (trigger 594592184.818686 / 191104854). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 288.4, Dec = 26.9 (J2000 degrees, equivalent to J2000 19h 13m, 26d 53'), with a statistical uncertainty of 14.7 degrees. The angle from the Fermi LAT boresight is 72.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104854/quicklook/glg_skymap_all_bn191104854.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104854/quicklook/glg_healpix_all_bn191104854.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2019/bn191104854/quicklook/glg_lc_medres34_bn191104854.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26166 SUBJECT: Fermi GBM GRB 191104C (trigger 594592184 / 191104854) is not a GRB DATE: 19/11/04 21:37:06 GMT FROM: Bagrat Mailyan at UAH B. Mailyan (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: “On 04 November 2019 at 20:29:39.82 UT the Fermi Gamma-ray Burst Monitor trigger 594592184 / 191104854 tentatively classified as a GRB (GRB 191104C in GCN #26165) is in fact not due to a GRB. This is a SGR-like burst from the direction of SGR 1935+2154." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26168 SUBJECT: Swift GRB191105.01: Global MASTER-Net OT detection DATE: 19/11/05 00:23:57 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres The Instituto de Astrofisica de Canarias V. Lipunov, E. Gorbovskoy, V.Kornilov, D.Kuvshinov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, F. Balakin Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University K. Ivanov, O. Gres, N.M. Budnev, S. Yazev, O. Chuvalaev, V. Poleshchuk Irkutsk State University A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov Kislovodsk Solar Station of the Pulkovo Observatory V. Yurkov, A. Gabovich, Yu. Sergienko Blagoveschensk Educational State University, Blagoveschensk D. Buckley, S. Potter, A. Kniazev, M. Kotze South African Astronomical Observatory R. Podesta, Carlos Lopez and F. Podesta Observatorio Astronomico Felix Aguilar (OAFA) Hugo Levato Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the GRB191105.01 38 sec after notice time and 57 sec after trigger time at 2019-11-05 00:09:55 UT. On our 3-th (30s exposure) set , obtained 134 sec after tigger time at 2019-11-05 00:11:13 UT, we found 1 optical transient within Swift error-box (ra=293.742 dec=21.9147 r=0.05) brighter than 14.22. T-Tmid Date Time Expt. Ra Dec Mag ---------|---------------------|-------|-----------------|-----------------|------- 149 2019-11-05 00:11:13 30 (19h 34m 49.505s , +21d 56m 28.09s) 13.98 The 5-sigma upper limit has been about 14.22mag The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26169 SUBJECT: Trigger 933276: Swift detection of further activity from SGR 1935+2154 DATE: 19/11/05 00:35:02 GMT FROM: David Palmer at LANL E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:08:58 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater SGR 1935+2154 (trigger=933276). Swift did not slew to this burst due to merit compared with the pre-planned target. The BAT on-board calculated location is RA, Dec 293.743, +21.915 which is RA(J2000) = 19h 34m 58s Dec(J2000) = +21d 54' 54" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a short peak structure with a duration of about 0.5 sec. The peak count rate was ~19000 counts/sec (15-350 keV), at ~0 sec after the trigger. This source has resumed activity 2019-11-04 UT with recent bursts listed in: Ambrosi, et al., GCN Circ. 26153 (1 burst) von Kienlein et al. GCN Circ. 26163 (6 bursts) B. Mailyan et al. GCN 26166 and previously unreported BAT bursts at 2019-11-04T01:54:37 2019-11-04T14:47:29 2019-11-04T14:53:05 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26170 SUBJECT: Swift GRB191105.01: Global MASTER-Net observations report DATE: 19/11/05 00:54:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), H.Levato (Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) MASTER-IAC robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Spain (IAC Teide Observatory) was pointed to the Swift GRB191105.01 (trigger No 933276,19h 34m 58.320s , +21d 54m 54.00s, R=0.05) errorbox 34 sec after notice time and 57 sec after trigger time at 2019-11-05 00:09:55 UT, with upper limit up to 15.6 mag. The observations began at zenith distance = 86 deg. The sun altitude is -74.9 deg. The galactic latitude b = -60 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1187352 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 62 | MASTER-IAC | P| | 10 | 13.1 | 105 | MASTER-IAC | P| | 20 | 14.5 | 150 | MASTER-IAC | P| | 30 | 14.7 | 197 | MASTER-IAC | P| | 40 | 14.7 | 256 | MASTER-IAC | P| | 50 | 15.2 | 325 | MASTER-IAC | P| | 60 | 15.6 | 412 | MASTER-IAC | P| | 70 | 15.6 | 505 | MASTER-IAC | P| | 90 | 15.0 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26162 SUBJECT: SGR 1935+2154: Swift-BAT refined analysis DATE: 19/11/04 15:06:58 GMT FROM: Scott Barthelmy at NASA/GSFC T. N. Ukwatta (LANL) E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), J. R. Cummings (CPI), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), (i.e. the Swift-BAT team): Using the data set from T-119 to T+183 sec from recent telemetry downlinks, we report further analysis of the BAT detection of a burst from SGR 1935+2154 (trigger #933083) (Ambrosi, et al., GCN Circ. 26153). The BAT ground-calculated position is RA, Dec = 293.741, 21.901 deg which is RA(J2000) = 19h 34m 57.8s Dec(J2000) = +21d 54' 02.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 85%. The lightcurve consists of a single peak with a total duration of ~0.04 sec. T90 (15-350 keV) is 0.03 +- 0.01 sec (estimated error including systematics). The time-averaged spectrum from T-0.00 to T+0.04 sec fit by a simple power-law model shows the power law index of 2.67 +- 0.31 (chi squared 38.4 for 57 d.o.f.). The fluence in the 15-150 keV band is 2.4 +- 0.4 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.48 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows the blackbody temperature of 6.16 +- 0.86 keV (chi squared 36.86 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 24.16 +- 7.80 keV (chi squared 36.5 for 57 d.o.f.). A double blackbody fit shows the lower temperature of 5.78 +0.95 keV and the higher temperature of 52.64 -7.00 keV (chi squared 30.61 for 55 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/933083/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26171 SUBJECT: Trigger 933285: Swift detection of the brightest burst so far from SGR 1935+2154 DATE: 19/11/05 01:51:58 GMT FROM: David Palmer at LANL E. Ambrosi (INAF-IASFPA), V. D'Elia (SSDC), J. A. Kennea (PSU) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 01:36:25 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from SGR 1935+2154 (trigger=933285). Swift did not slew due to merit considerations. The BAT on-board calculated location is RA, Dec 293.753, +21.896 which is RA(J2000) = 19h 35m 01s Dec(J2000) = +21d 53' 46" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak structure with a duration of about 0.5 sec. The peak count rate was ~130,000 counts/sec (15-350 keV), at ~0 sec after the trigger. The BAT software is designed to automatically set the trigger of each known source to twice the intensity seen with the previous trigger. Thus, each GCN notice for retriggering on the source indicates a burst at least twice as bright as the previous burst. In this case, the burst is about 7x as bright as reported in GCN 26169. This is the brightest burst seen so far in the the current activation of this source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26242 SUBJECT: Konus-Wind observation of the recent SGR 1935+2154 activity DATE: 19/11/13 14:22:57 GMT FROM: Anna Kozlova at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Since the renewal of bursting activity of the SGR 1935+2154 on October 4 (Wood & Bissaldi et al., GCN 25975, Ambrosi et al., GCN 26153, GCN 26169, GCN 26171; Burgess et al., GCN 26160; Ukwatta et al., GCN 26162; von Kienlin, GCN 26163) Konus-Wind have triggered on two bursts from this source. The following is a list of the Konus-Wind triggers with preliminary estimates of the burst fluences and peak fluxes. ------------------------------------------------------------------ Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 20191104 38666.612 s UT(10:44:26.612) 1.33 +/-0.07 17.0 +/-1.6 20191105 22268.832 s UT(06:11:08.832) 4.85 +/-0.15 29.4 +/-1.9 ------------------------------------------------------------------ * - Fluence (20-200 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-200 keV) on 16-ms time scale in units of 1e-6 erg/cm2/s The time-averaged spectra of the bursts are well fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------- # Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------- 1 0 - 0.128 0.47(-0.81,+0.91) 35(-4,+3) 6/13 2 0 - 0.192 -0.29(-0.34,+0.36) 42(-2,+2) 25/19 ------------------------------------------------------------- In terms of spectral parameters and peak fluxes these bursts are very similar to the intermediate flare from SGR 1935+2154 (Kozlova et al., MNRAS 460 2, 2016) and, assuming also their durations and fluences, are typical of short bursts detected by KW during the previous activation of the source. The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/191104_T38666/ http://www.ioffe.ru/LEA/SGRs/191105_T22268/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27527 SUBJECT: IPN Triangulation of a bright burst from SGR 1935+2154 DATE: 20/04/10 16:45:02 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, and A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, report: A bright, short-duration, soft burst has been observed by Fermi (GBM trigger 608204639) and Konus-Wind, so far, at about 35034 s UT (09:43:54) on April 10. We have triangulated it to a Konus-GBM annulus centered at RA(2000)=355.993 deg (23h 43m 58s) Dec(2000)=-0.325 deg (+0d 19' 31"), whose radius is 64.478 +/- 0.078 deg (3 sigma). This localization may be improved. The position of SGR 1935+2154 is inside the annulus at 4.2 arcmin from its center line. Given the positional coincidence of this burst with SGR 1935+2154, its time history, and softness of its spectrum (as observed by Konus- Wind and Fermi-GBM), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/200410_T35032/IPN/ The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27531 SUBJECT: SGR 1935+2154: Fermi GBM observation DATE: 20/04/10 21:37:38 GMT FROM: Peter Veres at UAH P. Veres (UAH), E. Bissaldi (Politecnico and INFN Bari) and M. S. Briggs (UAH) report on behalf of the Fermi GBM Team: "At 09:43:54.30 UT on 10 April 2020, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located an outburst from SGR 1935+2154 (trigger 608204639 / 200410405) which was also detected by the Konus-Wind (IPN) (Svinkin at al., GCN 27527). The GBM on-ground location is consistent with the known position of the SGR. The trigger was classified as a GRB by the flight software, but it is in fact from SGR 1935+2154. The angle from the Fermi LAT boresight at the GBM trigger time is 105 degrees. The light curve shows a short bright peak with a duration (T90) of about 128 ms (50-300 keV). The time-averaged spectrum from T0-64 ms to T0+192 ms is best fit by a power law function with an exponential high-energy cutoff. The power law index is 0.70 +/- 0.10 and the cutoff energy, parameterized as Epeak, is 32.7 +/- 0.3 keV The event fluence (10-1000 keV) in this time interval is (2.57 +/- 0.03)E-6 erg/cm^2. The 64-ms peak photon flux measured starting from T0 in the 10-1000 keV band is 489 +/- 9 ph/s/cm^2. We note that we see indications of saturation of only the TTE data at the brightest part of the pulse. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27554 SUBJECT: Konus-Wind observation of a bright burst from SGR 1935+2154 DATE: 20/04/12 15:26:22 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The bright burst from SGR 1935+2154 (IPN triangulation: Svinkin et al., GCN Circ. 27527, Fermi GBM observation: Veres et al., GCN Circ. 27531) triggered Konus-Wind at T0=35032.256 s UT (09:43:52.256) on 2020 April 10. The light curve shows a single pulse with a sharp rise and a total duration of ~0.2 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/SGRs/200410_T35032/ As observed by Konus-Wind, the burst had a fluence of 1.55(-0.08,+0.08)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.054 s, of 1.54(-0.15,+0.15)x10^-5 erg/cm2/s (both in the 20 - 200 keV energy range). The burst spectrum (measured from T0 to T0+0.128 s) is well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.15(-0.85,+0.99) and Ep = 28(-7,+4) keV (chi2 = 15/14 dof). A double blackbody function fits this spectrum equally well (chi2 = 15/13 dof), with the cold BB temperature of 6.9 (-4.6,+1.4) keV and the hot BB temperature of 13.0 (-3.6,+7.8) keV. Although this burst is more than order of magnitude less energetic than the 1.7s-long "intermediate" flare (IF) from this source on 2015 April 12 (Kozlova et al. 2016, MNRAS 460, 2008), its peak luminosity is almost comparable to that of the IF. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27625 SUBJECT: IPN Triangulation of a bright burst from SGR 1935+2154 DATE: 20/04/22 20:16:05 GMT FROM: Anna Ridnaia at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: A bright, short-duration, soft burst (CALET-GRBM detection: Cherry et al., GCN Circ. 27623) was detected by Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), CALET(GBM), and Swift (BAT) at about 31997 s UT (08:53:17) on April 22. The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 293.773 (19h 35m 05s) +21.942 (+21d 56' 31") Corners: 293.559 (19h 34m 14s) +21.634 (+21d 38' 02") 293.555 (19h 34m 13s) +21.991 (+21d 59' 27") 293.988 (19h 35m 57s) +22.248 (+22d 14' 52") 293.990 (19h 35m 58s) +21.893 (+21d 53' 33") --------------------------------------------- The error box area is 517 sq. arcmin, and its maximum dimension is 44 arcmin (the minimum one is 18 arcmin). The Sun distance was 91 deg. This box may be improved. The position of SGR 1935+2154 is inside the box at 3.5 arcmin from its center. Given the positional coincidence of this burst with SGR 1935+2154 (initially suggested in GCN Circ. 27623), its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude that this burst is likely originated from SGR 1935+2154. we conclude THAT this burst A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/200422_T31996/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27631 SUBJECT: Konus-Wind observation of a bright burst from SGR 1935+2154 DATE: 20/04/23 13:21:05 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The bright burst from SGR 1935+2154 (CALET-GRBM detection: Cherry et al., GCN Circ. 27623; IPN triangulation: Hurley et al., GCN Circ. 27625) triggered Konus-Wind at T0=31996.933 s UT (08:53:16.933) on 2020 April 22. The light curve shows a single pulse with a sharp rise and a total duration of ~0.6 s. The emission is seen up to ~250 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/SGRs/200422_T31996/ As observed by Konus-Wind, the burst had a fluence of 1.15(-0.03,+0.03)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.072 s, of 2.75(-0.23,+0.23)x10^-5 erg/cm2/s (both in the 20 - 200 keV energy range). The burst spectrum (measured from T0 to T0+0.256 s) is well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.06(-0.24,+0.25) and Ep = 52(-2,+2) keV (chi2 = 30/25 dof). A double blackbody function fits this spectrum less well (chi2 = 40/24 dof), with the cold BB temperature of 9.4 (-4.5,+1.9) keV and the hot BB temperature of 18.9 (-3.7,+5.3) keV. Among 17 bright bursts from SGR 1935+2154 detected by KW so far this event is the second most fluent (after the April 12, 2015 Intermediate Flare; Kozlova et al. 2016, MNRAS 460, 2008) and the second most luminous (after the November 5, 2019 burst; Ridnaia et al., GCN 26242). Also, the spectrum of the burst is characterized by the hardest peak energy so far; a typical Ep(CPL) for the KW sample is in the 30-40 keV range. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27657 SUBJECT: Swift detection of multiple bursts from SGR 1935+2154 DATE: 20/04/27 18:48:14 GMT FROM: David Palmer at LANL S. D. Barthelmy (GSFC), M. G. Bernardini (INAF-OAB), P. D'Avanzo (INAF-OAB), J.D. Gropp (PSU), J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB), D. M. Palmer (LANL), T. Sbarrato (INAF-OAB) and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift Observatory Team: At 18:26:20 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater SGR 1935+2154 (Trigger #968211). Because this is a known source Swift did not automatically slew. The on-board location is RA, Dec 293.735, +21.895 which is RA(J2000) = 19h 34m 56s Dec(J2000) = +21d 53' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single 64 ms bin with a peak count rate of 25k counts/sec (15-350 keV), at the time of the trigger. A second BAT trigger from this source was seen at 18:32:59 (trigger #968212) with comparable intensity. Follow-up observations with Swift are planned. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27659 SUBJECT: Fermi GBM observation of a bright flare from magnetar SGR 1935+2154 DATE: 20/04/28 02:28:30 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi GBM Team: "At 18:26:20.16 UT on 27 April 2020, the Fermi Gamma-Ray Burst Monitor triggered on a bright, SGR-like burst from the direction of the magnetar SGR 1935+2154 (trigger 609704785/ 200427768), which was also detected by the Swift/BAT (Barthelmy et al. 2020, GCN 27657). The burst has a duration (T90) of ~2 seconds in the energy range 10-200 keV. It is well-fit by a power law function with an exponential high-energy cutoff. The power law index is 0.02 +/- 0.68 and the cutoff energy, parameterized as Epeak, is 27.2 +/- 2.5 keV. The event fluence (10-200 keV) from T0-1.024 to T0+1.024 is (2.0 +/- 0.2)E-7 erg/cm^2. The average photon flux in the 10-200 keV band during this period is 2.5 +/- 0.2 ph/s/cm^2. Fermi GBM also subsequently triggered on multiple bursts from SGR 1935+2154 on 27 April 2020 with a fraction of these being misclassified as GRBs. The spectral analysis results presented above are preliminary. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/” //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27661 SUBJECT: SGR 1935+2154: MAXI/GSC detection DATE: 20/04/28 04:09:00 GMT FROM: Satoshi Nakahira at RIKEN Y. Sugawara, S. Nakahira (JAXA), H. Negoro, M. Nakajima (Nihon U.), M. Serino (AGU), M. Aoki, K. Kobayashi, R. Takagi, K, Asakura, K, Seino, S. Mokumoto (Nihon U.), T. Mihara, C. Guo, Y. Zhou, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Nishida, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano (Tokyo Tech), S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), T. Kawamuro (NAOJ), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered on two bright short bursts from the position consistent with that of an active Soft Gamma Repeater SGR 1935+2154 (GCN #27657, #27659, Atel #13675). Showing a double-peaked profile, the first one started at 20:01:45.99 of 2020-04-27 UT with a total duration of ~100 ms. The 5ms peak flux was about 75 Crab in the 2-20 keV band for each pulse. The second burst started at 21:56:02.63 UT with a single-peaked structure with a duration of 50 ms. This peak flux was about 40 Crab in 5 ms. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27662 SUBJECT: SGR 1935+2154 the Insight-HXMT observation plan DATE: 20/04/28 06:03:54 GMT FROM: Lin Lin at BNU L. Lin (BNU), S. M. Jia, S. N. Zhang (IHEP), report on behalf of the Insight-HXMT team: Since 18:26:20.16 UT on 27 April 2020, Multiple SGR-like bursts have been observed by Swift/BAT and Fermi/GBM from magnetar SGR 1935+2154 (Barthelmy et al. 2020,GCN 27657 and Fletcher et al. 2020, GCN 27659). And more bursts are coming in (Palmer et al. 2020, GCN 27660). Insight-HXMT is going to continuously observe SGR 1935+2154 for 60 ks from 2020-04-28 UTC 07:14:52 to 2020-04-29 UTC 11:53:01, with all its three sets of collimated detectors covering 1-15 keV, 5-30 keV and 20-250 keV, respectively. The net observing time intervals (in UT) without the Earth blockage of SGR 1935+2154 are as following: 2020-04-28 07:27:03 2020-04-28 08:28:32 2020-04-28 09:02:27 2020-04-28 10:03:55 2020-04-28 10:37:52 2020-04-28 11:39:18 2020-04-28 12:13:17 2020-04-28 13:14:41 2020-04-28 13:48:42 2020-04-28 14:50:04 2020-04-28 15:24:07 2020-04-28 16:25:27 2020-04-28 16:59:31 2020-04-28 18:00:50 2020-04-28 18:34:56 2020-04-28 19:36:13 2020-04-28 20:10:21 2020-04-28 21:11:36 2020-04-28 21:45:45 2020-04-28 22:46:58 2020-04-28 23:21:10 2020-04-29 00:22:21 2020-04-29 00:56:35 2020-04-29 01:57:44 2020-04-29 02:31:59 2020-04-29 03:33:07 2020-04-29 04:07:24 2020-04-29 05:08:30 2020-04-29 05:42:49 2020-04-29 06:43:53 2020-04-29 07:18:13 2020-04-29 08:19:16 2020-04-29 08:53:38 2020-04-29 09:54:39 2020-04-29 10:29:02 2020-04-29 11:30:02 SGR 1935+2154 went into outbursts in 2014 July, 2015 Feb., 2016 May and June (Lin et al. 2020). Several short bursts including very bright ones were detected in 2019 November and 2020 April by multi instruments. The source is now in a very active episode. We encourage multi-waveband follow up observations from both ground and space, especially the observations overlapping with Insight-HXMT. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27663 SUBJECT: high bursting activity of SGR 1935+2154: CGBM observations DATE: 20/04/28 06:45:35 GMT FROM: Valentin Pal'shin at AGU S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The CALET Gamma-ray Burst Monitor (CGBM) has been observing high bursting activity of SGR 1935+2154 since the CGBM trigger at ~18:32 UTC on 27 April 2020. No real-time CGBM GCN notice was distributed about this trigger because the real-time communication from the ISS was off (loss of signal). This trigger followed the Swift and Fermi-GBM triggers on bursts from SGR 1935+2154 at ~18:20 UTC reported in GCNs 27657, 27659, and 27660 (at this time CGBM HV was off). The CGBM data display a burst cluster along with multiple short bright bursts. The first CGBM trigger was shortly followed by another CGBM trigger at 18:46:08.675 UTC (trigger 1272047979: http://cgbm.calet.jp/cgbm_trigger/flight/1272047979/index.html) with several intense bursts. Additional two unalerted CGBM triggers with multiple short intense soft bursts were detected at ~20:15 UTC and ~21:49 UTC on 2020-04-27. After this, CGBM on-board trigger was disabled because it reached the maximum numbers of the accepted triggers. Further episodes of SGR activity were observed in CGBM TH data at ~23:18 UTC on 2020-04-27 and at ~00:43 - 00:57 UTC on 2020-04-28. Totally several tens of short bright SGR bursts have been detected by CGBM so far. So, SGR 1935+2154 did enter a new phase of activity as was suggested in GCN 27623. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27664 SUBJECT: SGR 1935+2154: AstroSat CZTI detections DATE: 20/04/28 11:37:58 GMT FROM: Varun Bhalerao at Indian Inst of Tech A. Marathe (NITK), V. Shenoy, V. Bhalerao (IITB), D. Bhattacharya (IUCAA), S. Vadawale (PRL), A. R. Rao (TIFR) report on behalf of the CZTI collaboration: Investigation of time series data over the last two days reveals the clear detections of multiple bursts in the data, originating from a direction consistent with outbursting SGR 1935+2154 (GCNs 27663, 27661, 27660, 27659, 27657, 27631, 27625, 27623, 27554, 27531, 27527). Owing to the limited localisation abilities of CZTI, we limit this report to bursts reported by other instruments. We see the following clear detections (UTC): 2020-04-27 at 18:32:59 2020-04-27 at 20:15:20 2020-04-28 at 00:44:07 Further analysis of data is under way. The source is close to the plane of detectors (angle from boresight, theta = 95 degrees), hence the incident photons are heavily reprocessed by the satellite before being incident on the detector. Any source spectrum inferences are unlikely. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27665 SUBJECT: A Forest of Bursts from SGR 1935+2154 DATE: 20/04/28 14:28:46 GMT FROM: David Palmer at LANL A Forest of Bursts from SGR 1935+2154 David M. Palmer (LANL) reports on behalf of the BAT Team: At 18:26:20 of 2020-04-27 UT, the Swift Burst Alert Telescope (BAT) triggered and located a burst from the Soft Gamma Repeater SGR 1935+2154 (Trigger #968211) (GCN #27657; Barthelmy et al.). This burst, and many subsequent bursts described below, continuing to at least T+7 hours (the time of this writing) were also seen by Fermi/GBM (GCN #27659; Fletcher et al.) This initial burst was followed by an intense sequence of bursts starting at ~T+300s after the first trigger time. This includes two separate time segments, 3 seconds and 15 seconds long, made up of rapid sequences of multiple bursts during which the count rate never returns to baseline on the 64 ms timescale (the highest time-resolution data that has been downlinked so far). During those time intervals, the peak count rate reaches up to 130k counts/s on a 64 ms timescale over the 15-350 keV band, and 350k counts/s on a 1 second timescale over the full detector sensitivity range. (The majority of these additional counts would be below the 15 keV calibrated energy bin but above the Low-Level-Discriminator level. This LLD level varies from detector-to-detector in BAT's 32k-element array, but is typically 12-14 keV. This indicates that the emission spectrum is very steep around those energies.) During the first 24 minutes of the episode, there were at least 35 clearly-distinguishable bursts outside of the piled-up time intervals. This is similar to the forests of bursts seen 2006-03-29 from SGR 1900+14 (Israel et al, 2008, ApJ 685:1114) and 2008-05-28 from SGR 1627-41. (GCN #7777; Palmer et al.). SGR 1935+2154's recent activation was first detected with a burst 5 days earlier, which was seen by multiple spacecraft, providing timing information that identified the location to be this source (GCN #27625; Hurley et al.). The previous BAT detection was 9 bursts in ~24 hours in November 2019. Note: A draft copy of this report was accidentally distributed to the GCN (as #27660) before the final version was submitted to ATel, and then as this courtesy copy to GCN. The ATel #13675 submission is the citable publication of record. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27667 SUBJECT: Konus-Wind observation of a very intense bursting activity of SGR 1935+2154 DATE: 20/04/28 18:47:28 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The onset of a new period of activity of SGR 1935+2154 (Swift-BAT detection: Barthelmy et al., GCN Circ. 27657, Palmer, GCN Circ. 27665; Fermi-GBM observation: Fletcher, GCN Circ. 27659; MAXI-GSC detection: Sugawara et al., GCN Circ. 27661; CALET-GBM observation: Ricciarini et al., GCN Circ. 27663; AstroSat-CZTI detection: Marathe et al., GCN Circ. 27664) has been detected by Konus-Wind on 2020 April 27. A series of several tens of bursts triggered Konus-Wind at 66696.729 s UT (18:31:36.729). The series consists of two very crowded clusters: from -0.252 s to 8 s and from 77 s to 116 s relative to the trigger time (numerous weaker bursts are seen between intense bursts). The most intense episode of the cluster started at ~85 s after trigger time. It had a duration of ~23.6 s, a fluence of 1.09(-0.02,+0.02)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+95.680 s, of 2.28(-0.27,+0.29)x10^-5 erg/cm2/s (both in the 20 - 200 keV energy range). The time-integrated spectrum of this cluster (measured from T0+74.496 to T0+91.392) is well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.48(-0.17,+0.18) and Ep = 35(-1,+1) keV (chi2 = 47/29 dof). A double blackbody function fits this spectrum equally well (chi2 = 38/28 dof), with the cold BB temperature of 4.7 (-0.5,+0.6) keV and the hot BB temperature of 12.5 (-0.4,+0.5) keV. The Konus-Wind light curve of this trigger is available at http://www.ioffe.ru/LEA/SGRs/200427_T66696/ Further SGR 1935+2154 bursts have triggered KW on 2020 April 27, so far, at 71024.348 s UT (19:43:44.348), 79162.174 s UT (21:59:22.174), and 85471.654 s UT (23:44:31.654). This burst cluster resembles the series of bursts from SGR 1900+14 and SGR 1806-20 detected about three months before giant flares from these sources observed on 1998 August 27 and 2004 December 27, respectively (Aptekar et al., ApJSS v. 137, p. 227, 2001, Golenetskii et al., GCN Circ. 2769, Golenetskii et al., GCN Circ. 2896). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27668 SUBJECT: SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst DATE: 20/04/29 09:30:38 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF S. Mereghetti (INAF, IASF-Milano), V. Savchenko (ISDC, Versoix), D. Gotz (CEA, Saclay), L. Ducci, C. Ferrigno, E. Bozzo (ISDC, Versoix), J.Borkowski (CAMK, Torun) and A. Bazzano (INAF, IAPS-Roma) report A bright short burst has been detected by IBAS in the IBIS/ISGRI data at 14:34:24 UT of April 28 (Alert Packet n. 8611), and promptly identified as originating from the currently active SGR 1935+2154 (GCN #27667, #27666, #27665, #27664, #27663, #27662, #27661, #27659, #27657, #27631, ATel #13682, #13679, #13678, #13675). Note that the above time is not corrected for the light-travel but it is consistent with the one of the radio burst from the same source reported in ATel #13681, #13684. The burst was at an off-axis angle of 8.1 degrees, in the field of view of the IBIS and SPI instruments, but outside those of JEM-X and OMC. A preliminary analysis indicates that the burst had a duration of about 0.3 s, a fluence of 3.9+/-0.2e-7 erg/cm2 in the 25-80 keV range and a peak flux of 1.2+/-0.1 e-6 erg/cm2/s on 10 ms timescale. The burst was also marginally detected in the SPI-ACS with S/N=4.65 on a 0.65s time scale. The ACS observation independently gives a FAP at the level of 0.0019 (2.9 sigma). We note that another weaker burst from SGR 1935+2154, lasting about 0.1 s was detected by IBAS at 09:51:05 UT of April 28 (Weak Alert Packet n. 8610). ISGRI and SPI-ACS lightcurves of the bright event are available at: https://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger=2020-04-28T14-34-23.4100-00000-00000-0 [GCN OPS NOTE(29apr20): Per author's request, the fluence in the 3rd paragraph was changed from "3.9+/-0.2e-5" to "3.9+/-0.2e-7 erg/cm2" (ie the value went down by 100x and units were added. A thank-you to V.Palshin for pointing out the typo.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27669 SUBJECT: Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154 DATE: 20/04/29 15:34:34 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The short burst from SGR 1935+2154 (INTEGRAL detection: Mereghetti et al., GCN Circ. 27668, Atel #13685; AGILE detection: Tavani et al., Atel #13686) triggered Konus-Wind at T0=52464.084 s UT (14:34:24.084) on 2020 April 28. The burst Earth-crossing time, T0Earth = 52464.444 s UTC (14:34:24.444), is consistent with the radio burst from SGR 1935+2154 reported in Scholz, ATel #13681 and Bochenek et al., Atel #13684. The light curve shows a multipeaked structure started at ~T0-0.2 s with a total duration of ~0.5 s. The emission is seen up to ~250 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/200428_T52464/ As observed by Konus-Wind, the burst had a fluence of 7.63(-0.75,+0.75)x10^-7 erg/cm2, and a 16-ms peak flux, measured from T0+0.004 s, of 9.10(-2.29,+2.29)x10^-6 erg/cm2/s (both in the 20 - 200 keV energy range). The burst spectrum (measured from T0 to T0+0.256 s) is well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.52(-0.50,+0.57) and Ep = 82(-9,+12) keV (chi2 = 14/24 dof). A double blackbody function fits this spectrum equally well (chi2 = 15/23 dof), with the cold BB temperature of 9.9 (-4.3,+3.9) keV and the hot BB temperature of 27.4 (-5.1,+9.2) keV. The burst temporal structure and hardness differ from a typical SGR burst and resemble the short hard bursts (Ep ~ 80 - 100 keV) associated with SGR 1900+14, observed on 1998 October 22 at 15:40:47.4 UT and on 1999 January 10 at 08:39:01.4 UT (Woods et al., ApJL 527, 47, 1999, Aptekar et al., ApJSS 137, 227, 2001), suggesting a possibly different emission mechanism of such SGR bursts. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27670 SUBJECT: SGR 1935+2154: MASTER optical observations DATE: 20/04/29 16:03:36 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, K.Zhirkov, V.Kornilov, E. Gorbovskoy, O.Gress, N.Tiurina,P.Balanutsa,A.Kuznetsov, F.Balakin,V.Vladimirov, D. Vlasenko, E.Minkina, I.Gorbunov, A.Chasovnikov, A.Pozdnyakov, D.Zimnukhov, V.Senik, T.Pogrosheva,D.Kuvshinov, V.Shumkov (Lomonosov Moscow State University, SAI, Physics Department), R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias), D. Buckley(South African Astronomical Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), R. Podesta, C.Lopez, F. Podesta, C.Francile(Observatorio Astronomico Felix Aguilar OAFA), H. Levato(Instituto de Ciencias Astronomicas, de la Tierra y del Espacio ICATE), N.M. Budnev, O.Ershova (Irkutsk State University, API), V. Yurkov, A. Gabovich, Yu. Sergienko(Blagoveschensk Educational State University) MASTER Global Robotic Net (http://observ.pereplet.ru,Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) started SGR 1935+2154 (Barthelmy et al., GCN 27657, 19h 34m 56s +21d 53' 43", er.b. 3') error-box observations at 2020-04-27 21:57:38UT (3.5h after Swift trigger). MASTER-Tavrida observed it since 2020-04-27 21:57:38UT to 2020-04-28 00:32:48UT with unfiltered mlim=20.0m (observations began at altitute 26deg, the sun altitude was -31deg.) MASTER-SAAO observed error-box since 2020-04-28 00:34:53 (target altitude 18deg, Sun alt.-57deg) to 2020-04-28 04:03:37UT with unfiltered mlim~19-20.2 MASTER-IAC observed error-box 1.5h since 2020-04-28 04:12:42 (target altitude = 66deg, sun alt.-23deg) with unfiltered mlim=19.7-20. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/event.php?id=1345392 The next alert of this SGR was from Integral (trigger time 2020-04-28 14:34:24 UT, Mereghetti et al. GCN 27668) MASTER-Amur and MASTER-Tunka observed it automatically started at 14:34:46UT (22s after trigger time) and at 2020-04-28 14:40:28 UT, Lipunov et al. GCN 27666. Real time updated cover map and possible OT will be available at: https://master.sai.msu.ru/site/master2/observ.php?id=1345998 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27671 SUBJECT: Fermi GBM trigger 200429866/609886052 is not a GRB DATE: 20/04/29 21:30:50 GMT FROM: Rachel Hamburg at UAH R. Hamburg (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: ¿The Fermi Gamma-ray Burst Monitor (GBM) trigger 200429866 / 609886052 at 20:47:27.98 UT on 29 April 2020, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to continued flaring from SGR 1935+2154 (GCN 27659)." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27672 SUBJECT: Trigger 968731: Swift detection of SGR1806-20 DATE: 20/04/30 13:10:14 GMT FROM: Scott Barthelmy at NASA/GSFC E. Ambrosi (INAF-IASFPA), S. D. Barthelmy (GSFC), V. D'Elia (SSDC), J.D. Gropp (PSU), J. A. Kennea (PSU), N. J. Klingler (PSU), A. Y. Lien (GSFC/UMBC) and K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift Observatory Team: At 12:56:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located SGR1806-20 (trigger=968731). Swift did not slew to the source because the merit value has been set low on this source. The BAT on-board calculated location is RA, Dec 272.131, -20.398, which is RA(J2000) = 18h 08m 32s Dec(J2000) = -20d 23' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single spike structure with a duration of about 0.2 sec. The peak count rate was ~3000 counts/sec (15-350 keV), at ~0 sec after the trigger. We plan shortly to execute a 2ks TOO observation with Swift in order to determine the flux state of this SGR. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27675 SUBJECT: Insight-HXMT X-ray and hard X-ray detection of the double peaks of the Fast Radio Burst from SGR 1935+2154 DATE: 20/05/01 18:23:45 GMT FROM: Shaolin Xiong at IHEP Zhang S.-N., Xiong S.-L., Li C.-K., Li X.-B., Tuo Y.-L., Ge M.-Y., Zhao X.-F., Xiao S., Jia S.-M., Nie J.-Y., Zhao H.-S., Luo Q., Li B., Cai C., Tan Y., Xue W.-C., Lu F.-J., Song L.-M., Liu C.-Z., Chen Y., Cao X.-L., Xu Y.-P., Li T.-P. (IHEP), Lin L. (BNU), Zhang B. (UNLV), on behalf of the Insight-HXMT team: Here we report a refined analysis of the Insight-HXMT light curves, which have been corrected for data saturation and dead-time effects. Insight-HXMT light curves could be found at: http://newshxmt.ihep.ac.cn/images/grb/SGR1935_3rd_atel.png The light curve in LE (1-10 keV) consists of two major bumps with a separation time of about 0.2 s. The first major bump in LE seems much brighter and wider than that in ME (10-30 keV) and HE (20-250 keV), while the second major bump are very bright in all three telescopes (HE, ME and LE), which was also detected by INTEGRAL (Atel #13685) and Konus-Wind (GCN #27669, Atel #13688). In addition, there is a minor soft bump in LE at the early phase of this flare which is marginally seen in ME data and absent in HE data. In HE and ME, there are two narrow peaks (14:34:24.4175 UT and 14:34:24.4475 UT) riding on the second major bump. In LE, these two narrow peaks are also visible, although the first peak is rather weak. Considering that the separation time between these two narrow peaks (~30 ms) is almost the same as that of the radio ones (~30 ms, Atel #13681), and that the apparent time lag between these two peaks and radio peaks (~8.6 s) is in perfect agreement with the calculated dispersion (8.63 s) between X-ray and radio using the measured DM (332.81 pc/cc) by CHIME/FRB (Atel #13681), we suggest that these two peaks are very likely the X-ray and hard X-ray counterparts of the double-peaked radio burst reported by CHIME/FRB (Atel #13681). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27678 SUBJECT: No optical bursts detected from SGR J1935+2154 by 24 fps observations with Tomo-e Gozen DATE: 20/05/03 03:06:16 GMT FROM: Yuu Niino at University of Tokyo Niino, Y., Morokuma, T., Sako, S., Ohsawa, R., Beniyama, J (U. of Tokyo), Kokubo, M (Tohoku U), on behalf of the Tomo-e Gozen collaboration We performed monitoring observations of SGR J1935+2154, from which intense burst activities have been found in the last few days (GCN #27657, #27659, #27661, #27663, #27664, #27665, #27667, #27668, #27669, #27675, ATel #13675, #13678, #13679, #13681, #13682, #13684, #13685, #13686, #13687, #13688, #13692, #13693, #13697), for 7 hrs (3.5 hrs starting UTC 2020-04-30 15:28 + 3.5 hrs starting UTC 2020-05-01 15:28) using the Tomo-e Gozen camera (optical CMOS imager, Sako et al. 2018, SPIE, 10702, 107020J) mounted on the 105-cm Kiso Schmidt telescope. The observations were conducted in a high-speed imaging mode with a frame rate of 24.4 fps (time resolution ~ 0.041 sec) and a 4.8x8 arcmin^2 FoV. Our quicklook analysis which degrades S/N of images by a factor of ~ 10 shows no apparent optical bursts above a 5-sigma limit of ~ 1 Jy ms. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27679 SUBJECT: Insight-HXMT X-ray and hard X-ray upper limits to the radio burst detected by FAST from SGR 1935+2154 DATE: 20/05/03 12:09:44 GMT FROM: Shaolin Xiong at IHEP C. K. Li, Y. L. Tuo, M. Y. Ge, X. B. Li, J. Y. Liao, C. Cai, S. L. Xiong, C. Z. Liu, Y. Chen, X. L. Cao (IHEP), T. P. Li (IHEP/THU), S. M. Jia, J. Y. Nie, F. J. Lu, L. M. Song, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), L. Lin (BNU), B. Zhang (UNLV), report on behalf of the Insight-HXMT team: Around the trigger time (T0=2020-04-30T21:43:00.5 UTC) of the highly polarised radio burst event reported by FAST (ATel #13699), Insight-HXMT was carrying out the ToO observation of SGR 1935+2154 without any occultation by the Earth. Within T0 +/- 50 s, no significant excess events (SNR > 3 sigma) are found in a search of the Insight-HXMT LE (1-10 keV), ME(10-30 keV) and HE (27-250 keV) light curves. Assuming the same spectral model to the X-ray counterpart that we reported in ATel #13687, and with one second timescale (1 s) coming from the position of SGR1935+2154, the 3-sigma fluence upper-limits are as following: Model: wabs*Cutoffpl (nH=2.6,PhoIndex=1.44, Ecut=69.8 keV): LE:  2.68e-09 erg cm^-2 ME:  3.45e-09 erg cm^-2 HE:  4.46e-09 erg cm^-2 Insight-HXMT will continue to observe SGR 1935+2154 with LE, ME and HE until 2020-05-06 01:20:47 UT. Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information could be found at: http://www.hxmt.org. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27681 SUBJECT: Geocentric time correction for Insight-HXMT detection of the x-ray counterpart of the FRB by CHIME and STARE2 from SGR 1935+2154 DATE: 20/05/03 16:19:09 GMT FROM: Shaolin Xiong at IHEP Zhang S.-N., Li C.-K., Zheng S.-J., Li X.-B., Tuo Y.-L., Ge M.-Y., Xiao S., Xiong S.-L., Zhao X.-F., Tan Y., Cai C., Jia S.-M., Nie J.-Y., Zhao H.-S., Luo Q., Li B., Lu F. J., Song L.-M., Liu C.-Z., Chen Y., Cao X.-L., Xu Y.-P., Li T.-P. (IHEP), Lin L. (BNU), Zhang B. (UNLV), on behalf of the Insight-HXMT team: In the Insight-HXMT light curves of SGR 1935+2154 we reported in Atel #13687 & #13696 and GCN #27675, the reference time (denoted as T0) of the burst is 14:34:24.5000 UT of April 28. Here we clarify that it is the arrival time at the Insight-HXMT satellite. Considering the position of the satellite in the geocentric coordinate system, the arrival time at the satellite is 11.443 ms earlier than the geocentric time, which means that T0 at the geocenter is 14:34:24.5114 UT of April 28, 2020. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27687 SUBJECT: AGILE detection of a short and hard X-ray burst possibly related to SGR 1935+2154 DATE: 20/05/04 11:34:49 GMT FROM: Francesco Verrecchia at SSDC,INAF-OAR  A. Ursi (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), C. Pittori (SSDC, and INAF/OAR),  A. Argan, M. Cardillo, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected a short hard X-ray burst at T0 = 2020-05-03 23:25:13.50 (UT). The event is visible in the scientific ratemeters of the SuperAGILE (SA; 20-60 keV) detector and of the Anti-Coincidence (AC, 50-200 keV). The event lasted ~0.5 s and released a total number of ~360 counts in the SA ratemeters (above a background of ~60 Hz) while ~800 counts in the AC ratemeters (above a background of ~4200 Hz). The SA and AC ratemeters light curves can be found at http://www.agilescienceapp.it/notices/AGILE_RM_SGR1935+2154_20200503.png . Considering the geometry of the satellite at T0, the burst detection is compatible with a source at the position of SGR 1935+2154. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27688 SUBJECT: Insight-HXMT detection of a short bright burst from SGR 1935+2154 DATE: 20/05/04 14:38:05 GMT FROM: Shaolin Xiong at IHEP Li X.-B., Li C.-K., Xue W.-C., Ge M.-Y., Xiong S.-L., Jia S.-M., Nie J.-Y., Zhao H.-S., Li B., Lu F.-J., Song L.-M., Liu C.-Z., Chen Y., Cao X.-L., Xu Y.-P., Li T.-P.,  Zhang S.-N.(IHEP), Lin L. (BNU), Zhang B. (UNLV), on behalf of the Insight-HXMT team: During the ToO observation to SGR 1935+2154, Insight-HXMT/HE detected a short (~0.2 s) and bright burst at 2020-05-03 23:25:13.4 UT (satellite time), which was also detected by Fermi/GBM (trigNum 610241118) and AGILE (GCN #27687). According to the relative rates in 17 detectors of HE (20-250 keV), this burst is consistent as from SGR 1935+2154. The HE light curve consists of two major bumps with a separation time of ~50 ms, and a relatively weaker but narrower peak, which is similar to the FRB-associated burst at 14:34:24.5 UT of April 28 (GCN 27675, Atel #13687, Atel #13696) but with a much higher peak flux. The HE light curves have been corrected for data saturation caused by the extreme brightness of this burst in HE. HE detectors are divided into 3 groups, i.e. PDAU 0, PDAU 1 and PDAU 2. Each group consists of 6 detectors and has implemented data saturation correction separately. The Insight-HXMT/HE light curve could be found at: http://newshxmt.ihep.ac.cn/images/grb/SGR1935_20200503T23.png After receiving the ME (5-30 keV) and LE (1-10 keV) data, more analysis results will be reported. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27700 SUBJECT: FRB/X-ray bursts from SGR 1935+2154: No Neutrino Counterpart in ANTARES data DATE: 20/05/08 20:44:49 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration. Following the detection of fast radio bursts (ATel #13681 , #13682 , #13684 ) accompanied with X-ray flares (GCN Circular #27657 , #27659 , #27661 ; ATel #13675 , #13678 , #13679 , #13685 , #13686 , #13687 , #13688 ), we have performed a search, using ANTARES data, for up-going muon neutrino candidates from the direction of SGR 1935+2154 in a time window of +/- 1h around the time of the X-ray trigger (14:34:24 UTC). At this time, the source was located 19 degrees below the horizon for ANTARES, and remained visible over the whole +/- 1h time window. No up-going muon neutrino candidate events were recorded at the location of the source. This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of 14 GeV.cm^-2 over the energy range 5.6 TeV – 5.4 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 30 GeV.cm^-2 (1 TeV - 515 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/- 1 day has also yielded no detection (38% visibility). ANTARES is the largest undersea neutrino detector (Mediterranean Sea) and it is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27714 SUBJECT: IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT DATE: 20/05/11 15:55:34 GMT FROM: Anna Ridnaia at Ioffe Institute K. Hurley, on behalf of the IPN, I. G. Mitrofanov, D. V. Golovin, A. S. Kozyrev, M. L. Litvak, and A. B. Sanin, on behalf of the HEND-Odyssey GRB team, A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, S. Barthelmy, J. Cummings, H. Krimm, and D. Palmer, on behalf of the Swift-BAT team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: A bright, short-duration, soft burst was detected by Konus-Wind, INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), CALET(GBM), and Swift (BAT) at about 22323 s UT (06:12:03) on May 10. The burst was outside the coded field of view of the BAT. We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 293.680 (19h 34m 43s) +21.858 (+21d 51' 27") Corners: 294.067 (19h 36m 16s) +22.043 (+22d 02' 34") 293.954 (19h 35m 49s) +22.349 (+22d 20' 58") 293.295 (19h 33m 11s) +21.669 (+21d 40' 09") 293.409 (19h 33m 38s) +21.360 (+21d 21' 36") --------------------------------------------- The error box area is 937 sq. arcmin, and its maximum dimension is 1.1 deg (the minimum one is 17 arcmin). The Sun distance was 104 deg. This box may be improved. The position of SGR 1935+2154 is inside the box at 3.7 arcmin from its center. Given the positional coincidence of this burst with SGR 1935+2154, its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude that this burst likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/200510_T22322/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27715 SUBJECT: Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10 DATE: 20/05/11 17:11:42 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Two bright, short bursts from SGR 1935+2154 (IPN triangulation: Hurley et al., GCN Circ. 27714) triggered Konus-Wind at 22322.624 s UT (06:12:02.624) and 78677.28 s UT (21:51:17.280) on 2020 May 10. The first burst light curve shows a single, very bright pulse started with a sharp rise and then smoothly decayed to the background level. The second burst light curve shows two pulses separated by a ~0.15 s gap. Both bursts have a total duration of ~0.4 s. The emission is seen up to ~500 keV. As measured by KW, the burst fluences and peak fluxes are as follows: ------------------------------------------------------------------ # Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 1 20200510 22322.624 s UT(06:12:02.624) 8.70 +/-0.22 38.9 +/-2.0 2 20200510 78677.280 s UT(21:51:17.280) 2.44 +/-0.10 17.8 +/-1.5 ------------------------------------------------------------------ * - Fluence (20-200 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-200 keV) on 16-ms time scale in units of 1e-6 erg/cm2/s The time-averaged spectra of the bursts are well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------- # Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------- 1 0 - 0.256 0.08(-0.23,+0.24) 47(-2,+2) 56/25 2 0 - 0.256 0.49(-0.65,+0.71) 37(-3,+2) 39/24 ------------------------------------------------------------- The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/200510_T22322/ http://www.ioffe.ru/LEA/SGRs/200510_T78677/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27718 SUBJECT: Insight-HXMT's continued observation plan for SGR J1935+2154 DATE: 20/05/12 08:53:10 GMT FROM: Shaolin Xiong at IHEP S.-N. Zhang, X.-B. Li, C.-K. Li, M.-Y. Ge, S.-L. Xiong, S.-M. Jia, J.-Y. Nie, H.-S. Zhao, C.-Z. Liu, Y. Chen, X.-L. Cao, Y.-P. Xu, F.-J. Lu, L.-M. Song (IHEP), T.-P. Li (THU/IHEP), on behalf of the Insight-HXMT team: Since 2020-04-28 07:14:51 UTC, Insight/HXMT has been observing SGR J1935+2154 under a public ToO. The current plan is to continue this public ToO until the end of May. An extended observation after May is probable if this SGR is still in active phase. Joint observations with Insight-HXMT are highly encouraged. The observation plan of Insight-HXMT can be found at: http://enghxmt.ihep.ac.cn/dqjh.jhtml Insight/HXMT data of this public ToO will be released very soon (i.e. a few days after observation), following to the data policy of Insight-HXMT. The data can be accessed at: http://hsuc.ihep.ac.cn/web We caution that significant data saturation may exist and is not corrected in the standard Insight-HXMT data products, since Insight-HXMT was not designed to handle very high counting rates. We are developing specific methods and codes to handle such data saturation, which have been applied successfully to the burst of SGR J1935+2154 associated with FRB 200428 (Atel #13687). However, these codes are not yet mature enough for public release. We thus suggest users of these data products be aware of these effects. For assistance on accessing and analyzing the Insight-HXMT data, please contact Dr. X.-B. Li at lixb@ihep.ac.cn As of May 10, 2020, about 100 bursts from SGR J1935+2154 have been found in a preliminary search of the raw data of HE, ME and LE. The online catalogue of SGR J1935+2154 bursts detected by Insight-HXMT could be found at: http://enghxmt.ihep.ac.cn/bfy/331.jhtml The sensitivities (3-sigma) of Insight-HXMT to short bursts are: HE (20 - 250 keV):  Fluence = 4.5E-9 * sqrt(T)  erg/cm2, ME ( 5 - 30  keV):  Fluence = 3.5E-9 * sqrt(T)  erg/cm2, LE ( 1 - 10  keV):  Fluence = 2.7E-9 * sqrt(T)  erg/cm2, where T is the burst duration in second. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27724 SUBJECT: SGR 1935+2154: AstroSat CZTI detection DATE: 20/05/12 18:58:13 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data showed the detection of a SGR 1935+2154, which was also detected by IPN (Hurley K. et al.,GCN #27714), Konus Wind (Ridnaia A. et al.,GCN #27715) and Insight-HXMT (Zhang S. et al., GCN #27718). The source was clearly detected in the 40-200 keV energy range. The light curve showed a single peak of emission peaking at 2020-05-10 06:12:00.750 UT. The measured peak count rate associated with the burst is 3283 +/- 61 cts/s above the background in the combined data of four quadrants, with a total of 1770 +/- 3 cts. The local mean background count rate was 566 +/- 1.0 cts/s. Using cumulative rates, we measure a T90 of 0.243 +/- 0.0004 s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The other burst detected by Konus Wind (UT: 21:51:17.280), wasn't detected due to Earth Occultation. CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 27727 SUBJECT: AGILE detection of a burst from SGR 1935+2154 on May 10, 2020 DATE: 20/05/12 21:01:28 GMT FROM: Francesco Verrecchia at SSDC,INAF-OAR F. Verrecchia (SSDC, and INAF/OAR), A. Ursi (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), C. Casentini (INAF/IAPS), M. Pilia (INAF/OA-Cagliari), C. Pittori (SSDC, and INAF/OAR),  A. Argan, M. Cardillo, Y. Evangelista, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected a short hard X-ray burst at T0 = 2020-05-10 06:12:03.5 (UT). For technical reasons data were processed with a delay of more than a day. The event is visible in the scientific ratemeters of the SuperAGILE (SA; 20-60 keV) detector and of the Anti-Coincidence (AC, 50-200 keV). The event lasted ~0.5 s and released a total number of ~100 counts in the SA ratemeter (above a background of ~43 Hz), and ~937 counts in the AC ratemeter (above a background of ~4700 Hz). The light curves of SA and AC ratemeters can be found at https://tools.ssdc.asi.it/ImgView/Agile/SGR1935burst_lc_2020-05-1027 . Considering the geometry of the satellite at T0, the burst detection is compatible with a source at the position of SGR 1935+2154 as determined in GCN #27714 (Hurley et al.). Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29363 SUBJECT: GECAM detection of a short burst probably from SGR 1935+2154 DATE: 21/01/27 08:14:10 GMT FROM: Shaolin Xiong at IHEP Y. Huang, S. J. Zheng, F. J. Lu, S. N. Zhang, L. M. Song, W. X. Peng, S. L. Xiong, S. Xiao, C. Cai, X. Y. Zhao, X. Ma, P. Zhang, B. X. Zhang, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, C. Y. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, Q. Luo, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, X. Y. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, W. C. Xue, S. Yang, M. Yao, Q. B. Yi, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, S. N. Zhang, Y. Q. Zhang, Z. Zhang, S. Y. Zhao, Y. Zhao, C. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a short burst (trig# 65429420) at 2021-01-27T06:50:20.750 UTC (T0). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of two pulses with a duration of roughly 100 ms. There is no much emission above 100 keV. The in-flight position (J2000) given by GECAM-B is: Ra: 291.31 deg Dec: 23.67 deg Galactic lon: 57.74 deg, lat: 3.63 deg Err: 2.16 deg (1-sigma, statistical only) The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_hrlc_grd_65429420.png The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_skymap_65429420.png According to the location and light curve, we suggest that this burst is very likely from SGR 1935+2154 which seems to be active recently. This is the first short trigger of GECAM which downlinked the high resolution light curve through BDS successfully. As the detailed science data are downloaded, all analyses would be improved. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29365 SUBJECT: IPN triangulation of a bright burst from SGR 1935+2154 DATE: 21/01/28 20:39:47 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, and S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, report: The bright, short-duration, soft burst (GECAM detection: Huang et al., GCN Circ. 29363) was detected by GECAM, Konus-Wind, and Swift (BAT) at about 24617 s UT (06:50:17) on January 27. The burst was outside the coded field of view of the BAT. We have triangulated it to a Konus-BAT annulus centered at RA(2000)=315.213 deg (21h 00m 51s) Dec(2000)=-14.116 deg (-14d 06' 56"), whose radius is 41.658 +/- 0.174 deg (3 sigma). The position of SGR 1935+2154 lies inside the annulus at 3.5 arcmin from its center line. Given the positional coincidence (initially suggested in GCN 29363) of this burst with SGR 1935+2154, its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/210127_T24616/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29373 SUBJECT: Konus-Wind detection of two bright bursts from SGR 1935+2154 DATE: 21/01/29 16:39:15 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Two bright, short bursts from SGR 1935+2154 (GECAM detection: Huang et al., GCN Circ. 29363 IPN triangulation: Ridnaia et al., GCN Circ. 29365) triggered Konus-Wind on 2021 January 27 at 24616.685 s UT (06:50:16.685), hereafter burst #1; and on 2021 January 29 at 25196.932 s UT (06:59:56.932), burst #2. The burst light curves feature a sharp rise, followed by a gradual decay, and, finally, a quick return of a count rate to the background level. Additionally, the main pulse of burst #1 is preceded by a weaker, partially overlapped sub-pulse. The burst total durations are ~100 ms (#1) and ~200 ms (#2). The emission in both bursts is seen up to ~200 keV. As measured by KW, the burst fluences and peak fluxes are as follows: ------------------------------------------------------------------ # Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 1 20210127 24616.685 s UT(06:50:16.685) 0.91 +/-0.07 16.0 +/-3.2 2 20210129 25196.932 s UT(06:59:56.932) 3.14 +/-0.11 27.5 +/-4.4 ------------------------------------------------------------------ * - Fluence (20-500 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-500 keV) on 2-ms time scale in units of 1e-6 erg/cm2/s Time-averaged spectra of the bursts are well fit by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------- # Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------- 1 0 - 0.064 -0.21(-1.00,+1.20) 31(-10,+5) 13/11 2 0 - 0.192 -0.33(-0.37,+0.40) 34(-3,+3) 14/20 ------------------------------------------------------------- These spectral parameters are typical of a few dosen SGR 1935+2154 short bursts detected by KW previously (with the notable exception of the April 28 SGR/FRB event). The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/210127_T24616/ http://www.ioffe.ru/LEA/SGRs/210129_T25196/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29377 SUBJECT: GECAM observations of SGR 1935+2154 DATE: 21/01/31 13:56:15 GMT FROM: Shaolin Xiong at IHEP P. Wang, C. Cai, X. Y. Zhao, X. B. Li, W. X. Peng, L. M. Song, S. L. Xiong, M. Y. Ge, S. J. Zheng, Y. Huang, X. Ma, S. Xiao, P. Zhang, B. X. Zhang, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, C. Y. Li, J. H. Li, Q. X. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, G. Ou, R. Qiao, D. L. Shi, J. Y. Shi, X. Y. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, W. C. Xue, S. Yang, M. Yao, Q. B. Yi, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, S. N. Zhang, Y. Q. Zhang, Z. Zhang, S. Y. Zhao, Y. Zhao, C. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: Since the first report of a bright burst from SGR 1935+2154 (Y. Huang et al., GCN 29363), GECAM has detected a series of bursts probably from this source, either from in-flight trigger or from ground search of the data. Here is the list of these bursts: TrigTime(UTC) 2021-01-27T06:50:20.750 2021-01-29T14:17:25.000 2021-01-29T17:51:00.850 2021-01-30T08:39:53.850 2021-01-30T09:46:01.050 2021-01-30T17:40:54.800 Locations of all these bursts are consistent with SGR 1935+2154. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29381 SUBJECT: INTEGRAL detection of a short burst from SGR 1935+2154 DATE: 21/02/02 20:20:57 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF S.Mereghetti (INAF, IASF-Milano), V.Savchenko, C.Ferrigno, E.Bozzo (ISDC, Versoix), D.Gotz (CEA, Saclay), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report: A burst from SGR 1935+2154, that is currently in an active state (e.g. GCN 29365, 29373, 29374, 29377), has been detected by IBAS in the IBIS/ISGRI data at 12:54:26.71 UT of February 2, 2021. The burst had a single peak lasting about 50 ms and a fluence of 1.14e-7 +/- 0.14e-7 erg/cm^2 in the 30-100 keV energy range. The off-line analysis confirmed the coordinates derived by IBAS and distributed in real time in the alert packet (n. 8965) that associated this event with SGR 1935+2154 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29383 SUBJECT: Recent activity of SGR 1935+2154 as observed by CGBM DATE: 21/02/03 00:27:16 GMT FROM: Valentin Pal'shin at AGU S. Ricciarini (U of Florence), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), P. S. Marrocchesi (U of Siena), and the CALET collaboration: During the recent reactivation of SGR 1935+2154 reported by GECAM (Huang et al., GCN Circ. 29363; Wang et al. GCN Circ. 29377), IPN (Ridania et al., GCN Circ. 29365), Konus-Wind (Ridnaia et al., GCN Circ. 29373), Fermi-GBM (Roberts et al., GCN Circ. 29374, ATel #14359), and INTEGRAL-IBAS (Mereghetti et al., GCN Circ. 29381) the CALET Gamma-ray Burst Monitor (CGBM) has triggered on three bright short soft bursts from this SGR (alerted triggers 1295912101, 1295951738, and 1296063650). Additional five weaker short soft bursts observed in the waiting mode (125-ms time resolution, 8 energy channels) with high S/N were also likely originated from SGR 1935+2154. The following table summarizes the bursts: Time, UTC Mode Other reported detections ------------------------------------------------------------- 2021-01-28 23:35:02.450 Trig Fermi-GBM 2021-01-29 02:46:23 BG Fermi-GBM 2021-01-29 10:35:39.707 Trig Fermi-GBM 2021-01-29 15:23:30 BG - 2021-01-29 21:15:56 BG Fermi-GBM 2021-01-30 13:05:39 BG - 2021-01-30 17:40:54.610 Trig GECAM 2021-01-31 03:01:28 BG - -------------------------------------------------------------- At the listed times, SGR 1935+2154 was in the FOVs of the CGBM detectors. The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29425 SUBJECT: SGR 1935+2154: MAXI/GSC detection DATE: 21/02/08 12:51:35 GMT FROM: Motoko Serino at RIKEN/MAXI T. Kawamuro (UDP/NAOJ), M. Serino (AGU), H. Negoro, M. Nakajima, M. Aoki, K. Kobayashi, R. Takagi, K. Asakura, K. Seino (Nihon U.), T. Mihara, T. Tamagawa, M. Matsuoka (RIKEN), T. Sakamoto, S. Sugita, H. Nishida, K. Komachi, A. Yoshida (AGU), Y. Tsuboi, W. Iwakiri, R. Sasaki, H. Kawai, Y. Okamoto, S. Kitakoga (Chuo U.), M. Shidatsu (Ehime U.), N. Kawai, R. Adachi, M. Niwano, R. Hosokawa (Tokyo Tech), S. Nakahira, Y. Sugawara, S. Ueno, H. Tomida, M. Ishikawa, M. Tominaga, T. Nagatsuka (JAXA), Y. Ueda, S. Yamada, S. Ogawa, K. Setoguchi, T. Yoshitake, Y. Goto, R. Uematsu (Kyoto U.), H. Tsunemi (Osaka U.), M. Yamauchi, K. Kurogi, K. Miike (Miyazaki U.), K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered on one short burst at 00:35:52 UTC on 2021/02/07 from a position consistent with an active Soft Gamma Repeater of SGR 1935+2154 (GCN 29363, 29365, 29373, 29374, 29377, 29381, 29383, 29388, Atel #14359). The duration of the burst is about 0.1 sec, and its 5 ms peak flux reached about 130 Crab in the 2-20 keV band. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30313 SUBJECT: Fermi GBM observation of a bright burst in the direction of SGR 1935+2154 DATE: 21/06/24 17:38:11 GMT FROM: Stephen Lesage at Fermi-GBM Team S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 02:34:10.19 UT on 24 June 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located a bright, SGR-like burst from the direction of the magnetar SGR 1935+2154 (trigger 646194855/210624107). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 293.73, Dec = 21.90 (J2000 degrees), with a statistical uncertainty of 2.72 degrees and is consistent with the known position of the SGR. The angle from the Fermi LAT boresight at the GBM trigger time is 37 degrees. The burst has a duration (T90) of about 0.08 s (10-300 keV). It is best fit by a double-blackbody model with temperatures of kT1 = 7.4 +/- 0.7 keV and kT2 = 13.3 +/- 1.5 keV. The event fluence (10-300 keV) from T0-0.016s to T0+0.064s is (1.16 +/- 0.03)E-06 erg/cm^2. The average photon flux in the 10-300 keV band during this period is 194 +/- 4 ph/s/cm^2. The spectral analysis results presented above are preliminary. For Fermi GBM data and info, please visit the official Fermi GBM Support Page:https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30395 SUBJECT: INTEGRAL detection of a burst from SGR 1935+2154 DATE: 21/07/06 19:25:57 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF S.Mereghetti (INAF, IASF-Milano) on behalf of the IBAS localization team reports: A short burst has been detected by IBAS in the IBIS/ISGRI data at 17:14:50.7 UT of 2021 July 6. The burst was clearly localized at the position of the galactic magnetar SGR 1935+2154 and a notice with the source identification was distributed in real time (IBAS Alert Packet n.9294). The burst had a duration of about 50 ms. A preliminary analysis indicates a fluence of about 1e-7 erg/cmq (20-200 keV). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30400 SUBJECT: GECAM detection of a bright short burst from SGR 1935+2154 DATE: 21/07/07 03:43:28 GMT FROM: Shuo Xiao at IHEP S. Xiao, Y. Huang, X. Y. Zhao, S. L. Xiong, W. C. Xue, X. Y. Song, C. Cai, S. L. Xie, J. C. Liu, C. Y. Li, Y. Q. Zhang, Y. Zhao, Z. W. Guo, C. Zheng, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a bright short burst (trig# 79317211) at 2021-07-07T00:33:31.700 UTC (T0), which was also observed by Fermi/GBM (trig# bn210707023). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of two overlapping pulses with a duration of about 100 ms. Using the light curves and spectrum in the BDS alert data, GECAM-B localized this burst to the following position (J2000): Ra: 291.99 deg Dec: 24.30 deg Err: 3.07 deg (1-sigma, statistical only) The current systematic error of location is estimated to be several degrees. This location is consistent with SGR J1935+2154 within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/79317211_lc.png The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_skymap_bdm_79317211_V01.png Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30406 SUBJECT: Swift-BAT detection of a burst from SGR 1935+2154 DATE: 21/07/07 14:54:59 GMT FROM: David Palmer at LANL D. M. Palmer (LANL) on behalf of the Swift team reports: A short burst has been detected by the BAT instrument at 23:59:32.6 on 2021-07-04 UT from SGR 1935+2154. The burst had a duration of about 150 ms with a peak count rate of 2,000 counts/second (15-350 keV on the 64 ms timescale). The burst reported from the same source by INTEGRAL at 17:14:50.7 of 2021-07-06 UT (GCN #30395 Mereghetti et al.) is also detected as a count rate increase in BAT of 65,000 counts/s on the 64 ms timescale. However, Swift was slewing at that time and so BAT could not localize the source. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30409 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 6 DATE: 21/07/07 16:48:03 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short burst from SGR 1935+2154 (INTEGRAL detection: Mereghetti, GCN 30395) triggered Konus-Wind on 2021 July 6 at T0=62093.331 s UT (17:14:53.331). The burst light curve features a sharp rise, followed by a gradual decay, and, finally, a quick return of a count rate to the background level. The burst total duration is ~50 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/210706_T62093/ As observed by Konus-Wind, the burst had a fluence of 8.90(-0.22,+1.45)x10^-7 erg/cm2, and a 2-ms peak flux, measured from T0-0.004 s, of 2.56(-0.43,+0.60)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). Since the brightest part of the burst emission was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modelling the time-integrated spectrum of the burst (measured from T0-0.038 to T0+0.018 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), yields alpha = -1.15(-0.72,+2.34) and Ep = 23(-17,+16) keV. All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30415 SUBJECT: GECAM detection of a short burst from SGR 1935+2154 DATE: 21/07/08 08:02:15 GMT FROM: Ce Cai at IHEP C. Cai, S. L. Xiong, S. Xiao, Y. Huang, X. Y. Zhao, W. C. Xue, X. Y. Song, S. L. Xie, J. C. Liu, C. Y. Li, Y. Q. Zhang, Y. Zhao, Z. W. Guo, C. Zheng, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a short burst (trig# 79402698) at 2021-07-08T00:18:18.850 UTC (T0). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of a single pulse with a duration of about 100 ms. The location is consistent with SGR J1935+2154 within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_79402698.png As the detailed science data are downloaded, all analyses would be improved. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30418 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 7 DATE: 21/07/08 15:20:32 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short burst from SGR 1935+2154 (GECAM detection: Xiao et al., GCN 30400; Fermi GBM Observations: Hamburg et al., GCN 30407) triggered Konus-Wind on 2021 July 7 at T0=2015.644 s UT (00:33:35.644). The burst light curve shows a single pulse with a total duration of ~120 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/SGRs/210707_T02015/ As observed by Konus-Wind, the burst had a fluence of 1.48(-0.08,+0.08)x10^-6 erg/cm2, and a 2-ms peak flux, measured from T0-0.014 s, of 1.94(-0.39,+0.39)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.43(-0.80,+0.88) and Ep = 38(-4,+3) keV (chi2 = 12/14 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30430 SUBJECT: GECAM detection of a short burst from SGR 1935+2154 DATE: 21/07/09 12:46:46 GMT FROM: Ce Cai at IHEP C. Cai, S. L. Xiong, S. Xiao, Y. Huang, X. Y. Zhao, W. C. Xue, X. Y. Song, S. L. Xie, J. C. Liu, C. Y. Li, Y. Q. Zhang, Y. Zhao, Z. W. Guo, C. Zheng, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, J. H. Li, Q. X. Li, X. B. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou, W. X. Peng, R. Qiao, D. L. Shi, J. Y. Shi, L. M. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, C. W. Wang, J. Z. Wang, P. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, Q. B. Yi, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a short burst (trig# 79528675) at 2021-07-09T11:17:55.000 UTC (T0). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the BDS alert data, this burst mainly consists of a single pulse with a duration of about 100 ms. Using the light curves and spectrum in the BDS alert data, GECAM-B localized this burst to the following position (J2000): Ra: 297.00 deg Dec: 25.64 deg Err: 10.87 deg (1-sigma, statistical only) The current systematic error of location is estimated to be several degrees. This location is consistent with SGR J1935+2154 within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_79528675.png As the detailed science data are downloaded, all analyses would be improved. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30450 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2021 July 10 DATE: 21/07/12 12:53:17 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short, soft burst from SGR 1935+2154 (Fermi GBM trigger 647641569) triggered Konus-Wind on 2021 July 10 at T0=73568.532 s UT (20:26:08.532). The burst light curve shows a single pulse started at ~T0-150 ms with a total duration of ~200 ms. The emission is seen up to 200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/210710_T73568/ As observed by Konus-Wind, the burst had a fluence of 1.49(-0.17,+0.17)x10^-6 erg/cm2, and a 2-ms peak flux, measured from T0-0.044 s, of 1.33(-0.33,+0.33)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.66(-1.32,+1.91) and Ep = 25(-22,+9) keV (chi2 = 6/9 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30458 SUBJECT: Recent activity of SGR 1935+2154 as observed by CGBM DATE: 21/07/13 09:59:01 GMT FROM: Valentin Pal'shin at AGU S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita (AGU), Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: During the recent reactivation of SGR 1935+2154 reported by INTEGRAL (GCN 30395), GECAM (GCNs 30400, 30415, 30430, 30437, 30449), Fermi-GBM (GCN 30407), and Konus-Wind (GCNs 30409, 30418, 30450) the CALET Gamma-ray Burst Monitor (CGBM) has triggered on two bright short soft bursts from this SGR (alerted trigger 1309652996: http://cgbm.calet.jp/cgbm_trigger/flight/1309652996/ and trigger 1309983742, which was not alerted). Additional two weaker short soft bursts observed in the waiting mode (125-ms time resolution, 8 energy channels) with high S/N were also likely originated from SGR 1935+2154 (these bursts have not been reported by other instruments so far). The following table summarizes the bursts: Time, UTC Mode Other reported detections -------------------------------------------------------------- 2021-07-07 00:33:31.593 Trig GECAM,Fermi GBM,Konus-Wind 2021-07-10 20:26:04.635 Trig* Konus-Wind,Fermi GBM 2021-07-11 14:42:55 BG - 2021-07-12 16:58:51 BG - -------------------------------------------------------------- *- Because of a problem in one of the ground alert processing script, the GCN notice was not distributed automatically for this trigger. At the listed times, SGR 1935+2154 was in the FOVs of the CGBM detectors. The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30598 SUBJECT: IPN Triangulation of a bright burst from SGR 1935+2154 DATE: 21/08/07 02:29:56 GMT FROM: Dmitry Svinkin at Ioffe Institute D. Svinkin, S. Golenetskii, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, and A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, report: A bright, short-duration, soft burst has been observed by Konus-Wind, INTEGRAL (SPI-ACS), and Swift (BAT), so far, at about 536 s UT (00:08:56) on August 5. The burst was outside the coded field of view of the BAT. We have triangulated it to a Konus-BAT annulus centered at RA(2000)=313.877 deg (20h 55m 31s) Dec(2000)=-20.391 deg (-20d 23' 28"), whose radius is 46.762 +/- 0.249 deg (3 sigma) and to a Konus-SPI-ACS annulus centered at RA(2000)=310.504 deg (20h 42m 01s) Dec(2000)=-16.410 deg (-16d 24' 34"), whose radius is 41.919 +/- 0.512 deg (3 sigma). This localization may be improved. The position of SGR 1935+2154 is inside the annuli at 7.2 arcmin from the center line of the Konus-BAT annulus. Given the positional coincidence of this burst with SGR 1935+2154, its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/210805_T00539/IPN/ The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30599 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2021 August 5 DATE: 21/08/07 06:42:27 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short, soft burst from SGR 1935+2154 (IPN triangulation: Svinkin et al., GCN 30598) triggered Konus-Wind on 2021 August 5 at T0=539.958 s UT (00:08:59.958). The burst light curve shows a single pulse started at ~T0-70 ms with a total duration of ~165 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/SGRs/210805_T00539/ As observed by Konus-Wind, the burst had a fluence of 1.29(-0.08,+0.08)x10^-6 erg/cm2, and a 2-ms peak flux, measured from T0-0.014 s, of 1.62(-0.35,+0.35)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.39(-0.99,+1.12) and Ep = 33(-6,+4) keV (chi2 = 11/12 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30631 SUBJECT: SGR 1935+2154: SPI INTEGRAL observations on 2021 August 5 DATE: 21/08/12 16:50:44 GMT FROM: Alexei Pozanenko at IKI, Moscow I. Chelovekov (IKI), A. Pozanenko (IKI), P. Minaev (IKI), S. Grebenev (IKI) report on behalf of the GRB IKI FuN: Using publicly available data of the INTEGRAL/SPI telescope we localized the source of the gamma-ray outburst detected by Konus/WIND (Ridnaia et al., GCB 30599), ASC/INTEGRAL and BAT/Swift on August 5, 2021 and triangulated by IPN (Svinkin et al., GCB 30598). Duration of the event in the SPI above 20 keV is 0.14 s. Its time profile is shown at http://grb.rssi.ru/SGR1935+2154/SGR1935+2154_SPI_LC_2101-08-05.png The source was detected at the edge of the SPI FOV (15.07 deg off the telescope axis). The map of the sky within the SPI FOV obtained during the outburst is given at http://grb.rssi.ru/SGR1935+2154/SGR1935+2154_SPI_2101-08-05.png The coordinates of the source, (J2000) R.A.=294.0 deg, Decl.=21.7 deg, are determined with an uncertainty of 0.4 deg (radius). The position of the source coincides with that of SGR 1935+2154. Thus we can confirm that the outburst on August 5, 00:08:56 (UT) is a part of activity of SGR 1935+2154. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30803 SUBJECT: IPN triangulation of a bright burst from SGR 1935+2154 DATE: 21/09/10 20:59:57 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, D. Frederiks, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, K. Hurley, on behalf of the IPN, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi-GBM team, and S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu on behalf of the Swift-BAT team, report: A bright, short-duration, soft burst has been observed by Fermi (GBM), Konus-Wind, and Swift (BAT), so far, at about 2747 s UT (00:45:47) on September 10. The burst was outside the coded field of view of the BAT. We have triangulated it to a Konus-GBM annulus centered at RA(2000)=326.594 deg (21h 46m 22s) Dec(2000)=-14.741 deg (-14d 44' 28"), whose radius is 48.801 +/- 0.199 deg (3 sigma). This localization may be improved. The position of SGR 1935+2154 lies inside the annulus at 0.7 arcmin from its center line. Given the positional coincidence of this burst with SGR 1935+2154, its time history, softness of its spectrum (as observed by Konus-Wind), and reported bursting activity (Xiao et al., GCN Circ. 30797), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/210910_T02750/IPN/ The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30804 SUBJECT: Konus-Wind detection of the second intermediate flare from SGR 1935+2154 DATE: 21/09/10 21:03:57 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The very bright burst from SGR 1935+2154 (IPN triangulation: Ridnaia et al., GCN Circ. 30803) triggered Konus-Wind at T0=2750.499 s UT (00:45:50.499) on 2021 September 10. The light curve shows a single pulse with a sharp(<10 ms) rise and a total duration of ~1.4 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/210910_T02750/ As observed by Konus-Wind, the burst had a fluence of 2.51(-0.04,+0.04)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.322 s, of 3.09(-0.18,+0.18)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.512 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.21(-0.18,+0.19) and Ep = 52(-1,+1) keV (chi2 = 37/22 dof). The rather long duration of the burst along with the large measured energy fluence put the burst in the class of "intermediate" SGR bursts. The event is as fluent as the April 12, 2015 Intermediate Flare (Kozlova et al. 2016, MNRAS 460, 2008); the spectrum of the burst is characterized by the higher peak energy than of the April 12, 2015 IF (Ep~35 keV). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30806 SUBJECT: Fermi GBM observation of a bright flare in the direction of SGR 1935+2154 DATE: 21/09/11 00:20:44 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA/NASA-MSFC), J. Wood (USRA/NASA-MSFC), report on behalf of the Fermi GBM Team: "At 00:45:46.94 UT on 10 September 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located a bright, SGR-like flare from the direction of the magnetar SGR 1935+2154 (trigger 652927551/210910032). The flare was also observed by Konus Wind (Ridnaia et al., GCN 30804) and triangulated to an annulus incorporating the SGR position by the IPN (Ridnaia et al., GCN 30803). The on-ground calculated location using the Fermi GBM trigger data, is consistent with the known position of the SGR and the IPN localization. The angle from the Fermi LAT boresight at the GBM trigger time is 102 degrees. The burst has a duration (T90) of about 1.4 s (10-1000 keV). It is best fit by a double-blackbody model with temperatures of kT1 = 8.51 +/- 0.08 keV and kT2 = 16.55 +/- 0.18 keV. The event fluence (10-1000 keV) from T0-0.064s to T0+1.328s is (3.858 +/- 0.011)E-05 erg/cm^2. The average photon flux in the 10-1000 keV band during this period is 522.7 +/- 1.5 ph/s/cm^2. Fermi GBM has also triggered on 14 other bursts from the direction of SGR 1935+2154 over the last 4 days, indicating it has entered a stage of heightened activity in this latest outburst: Date and Time in UTC Fermi MET (s) 2021-09-06T01:44:30.10 652585475 2021-09-09T18:57:14.86 652906639 2021-09-09T20:21:28.37 652911693 2021-09-10T00:45:46.94 652927551 2021-09-10T01:00:43.71 652928448 2021-09-10T01:13:17.40 652929202 2021-09-10T01:27:05.60 652930030 2021-09-10T02:21:06.44 652933271 2021-09-10T02:36:38.24 652934203 2021-09-10T02:55:10.17 652935315 2021-09-10T05:35:55.51 652944960 2021-09-10T09:12:48.91 652957973 2021-09-10T15:50:56.89 652981861 2021-09-10T23:40:34.46 653010039 The spectral analysis results presented above are preliminary. We encourage multi-wavelength observations to follow-up this most recent activation. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30831 SUBJECT: Fermi GBM observation of another bright burst in the direction of SGR 1935+2154 DATE: 21/09/13 03:33:14 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA/NASA-MSFC) reports on behalf of the Fermi GBM Team: "At 20:16:10.44 UT on 12 September 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located a bright, SGR-like burst from the direction of the magnetar SGR 1935+2154 (trigger 653170575/210912845). The GBM on-ground location is consistent with the known position of the SGR. The angle from the Fermi LAT boresight at the GBM trigger time is 96 degrees. The event episode has a duration (T90) of about 1 s (10-1000 keV). During this time interval, there are several very short bursts. The first burst has a rapid risetime. The whole event is best fit with a power law function with an exponential high-energy cutoff. The power law index is 0.08 +/- 0.08 and the cutoff energy, parameterized as Epeak, is 32.1 +/- 0.3 keV. The time-integrated event fluence (10-1000 keV) from T0-0.064 to T0+0.944s is (3.545 +/- 0.038)E-6 erg/cm^2. The average photon flux in the 10-1000 keV band during this period is 84 +/- 1 ph/s/cm^2. Fermi GBM has also triggered on a further 24 bursts from the direction of SGR 1935+2154 since yesterday's GCN (Roberts and Wood, GCN 30806): Date and Time in UTC Fermi MET (s) 2021-09-12T23:19:32.08 653181577 2021-09-12T20:16:10.44 653170575 2021-09-12T15:03:50.60 653151835 2021-09-12T13:55:16.45 653147721 2021-09-12T12:19:20.44 653141965 2021-09-12T10:10:11.73 653134216 2021-09-12T07:28:07.46 653124492 2021-09-12T06:51:13.22 653122278 2021-09-12T05:14:07.84 653116452 2021-09-11T02:36:38.24 653093506 2021-09-11T20:22:59.04 653084584 2021-09-11T20:05:46.22 653083551 2021-09-11T18:54:36.05 653079281 2021-09-11T17:01:09.77 653072474 2021-09-11T16:50:03.83 653071808 2021-09-11T16:36:57.91 653071022 2021-09-11T15:26:11.55 653066776 2021-09-11T15:15:25.44 653066130 2021-09-11T15:03:00.55 653065385 2021-09-11T13:27:33.85 653059658 2021-09-11T11:53:57.29 653054042 2021-09-11T10:42:51.85 653049776 2021-09-11T05:32:38.65 653031163 2021-09-11T03:02:28.36 653022153 Fermi GBM will not report on future triggers from this event. The spectral analysis results presented above are preliminary. We encourage multi-wavelength observations to follow-up this most recent activation. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30835 SUBJECT: AGILE observations of two bright bursts from SGR 1935+2154 DATE: 21/09/13 13:06:58 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), E. Menegoni, L. Foffano (INAF/IAPS), V. Fioretti (INAF/OAS-Bologna), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Pacciani, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite clearly detected the two bright bursts from the SGR1935+2154, at T1 = 2021-09-10 00:45:47 s (UTC), reported by Konus-Wind (GCN #30804), Fermi GBM (GCN #30806), and GECAM (GCN #30822), and at T2 = 2021-09-12 20:16:10 s (UTC), reported by Fermi GBM (GCN #30831). The bursts are clearly visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV) and AntiCoincidence (AC; 50-200 keV) detectors. The first event lasted about 2 s and it released a total number of 560 counts in the SA detector (above a background rate of 65 Hz), and 8730 counts in the AC detector (above a background rate of 3450 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/burst210910_AGILE_RM.png . At T1, the SGR1935+2154 was 150 deg off-axis for AGILE. The second event lasted 2 s and it released a total number of 620 counts in the SA detector (above a background rate of 100 Hz), and 8170 counts in the AC detector (above a background rate of 3500 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/burst210912_AGILE_RM.png . At T2, the SGR1935+2154 was 37 deg off-axis for AGILE. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30838 SUBJECT: Konus-Wind observation of the recent SGR 1935+2154 activity DATE: 21/09/13 17:56:37 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, S. Golenetskii, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Since the last KW GCN on the ongoing SGR 1935+2154 activity (Ridnaia et al., GCN 30803) the instrument triggered on four bright bursts from the source. The following is a list of the Konus-Wind triggers with preliminary estimates of the burst fluences and peak fluxes. ------------------------------------------------------------------ # Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 1 20210911 54406.825 s UT(15:06:46.825) 5.38 +/-0.15 22.6 +/-1.6 2 20210911 61274.025 s UT(17:01:14.025) 7.84 +/-0.21 18.5 +/-1.4 3 20210912 24677.185 s UT(06:51:17.185) 4.96 +/-0.14 26.6 +/-1.7 4 20210912 28904.121 s UT(08:01:44.121) 1.25 +/-0.02 17.0 +/-1.4 ------------------------------------------------------------------ * - Fluence (20-500 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-500 keV) on 16-ms time scale in units of 1e-6 erg/cm2/s The time-averaged spectra of the bursts are well fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------------ # T100 Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------------ 1 0.392 0 - 0.256 0.47(-0.32,+0.33) 42(-2,+2) 30/20 2 1.243 0 - 8.448 0.40(-0.37,+0.39) 37(-2,+1) 36/28 3 0.452 0 - 0.256 0.20(-0.35,+0.37) 38(-2,+2) 17/19 4 1.600 0 - 8.448 -0.10(-0.21,+0.22) 35(-1,+1) 43/29 ------------------------------------------------------------------ The emission in all bursts is seen up to ~200 keV. The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/210911_T54406/ http://www.ioffe.ru/LEA/SGRs/210911_T61274/ http://www.ioffe.ru/LEA/SGRs/210912_T24677/ http://www.ioffe.ru/LEA/SGRs/210912_T28904/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30866 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2021 September 22 DATE: 21/09/23 12:31:24 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, S. Golenetskii, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: A short, soft, SGR-like burst triggered Konus-Wind on 2021 September 22 at T0=72739.639 s UT (20:12:19.639). The Konus-Wind ecliptic latitude response is consistent with the SGR 1935+2154 position. So, taking in account the ongoing bursting activity of this source, burst time history, and softness of its spectrum (as observed by Konus-Wind), we suggest that this burst is likely originated from SGR 1935+2154. The burst light curve shows a single pulse started at ~T0-100 ms with a total duration of ~172 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/210922_T72739/ As observed by Konus-Wind, the burst had a fluence of 1.46(-0.08,+0.08)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.024 s, of 1.59(-0.16,+0.16)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.13(-0.76,+0.85) and Ep = 37(-6,+4) keV (chi2 = 12/14 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30916 SUBJECT: SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization DATE: 21/10/01 18:01:34 GMT FROM: Aaron Tohuvavohu at U Toronto Aaron Tohuvavohu (U Toronto), James DeLaunay (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU) report: Swift/BAT did not localize SGR 1935+2154 (T0: 2021-10-01 00:04:04.3 UTC, Fermi/GBM trigger # 654739449) onboard. The Fermi/GBM notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu, in prep), detects a burst and localizes it to the position of SGR 1935+2154. The burst is detected in BAT with a duration of less than 64 ms. This position is consistent with the Ferm/GBM localization. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31296 SUBJECT: AGILE observations of a bright burst from SGR 1935+2154 DATE: 21/12/24 13:48:27 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), G. Piano, E. Menegoni, L. Foffano (INAF/IAPS), V. Fioretti (INAF/OAS-Bologna), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, L. Pacciani (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite clearly detected a bright burst from the SGR1935+2154, at T0 = 2021-12-24 03:42:34 s (UTC), reported by Fermi GBM (Fermi GBM Trigger bn211224155). The burst is clearly visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV) and AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 2 s and it released a total number of 360 counts in the SA detector (above a background rate of 110 Hz), and 9250 counts in the AC detector (above a background rate of 2960 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/SGR1935+2154_AGILE_RM.png . At T0, the SGR1935+2154 was 46 deg off-axis for AGILE. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31325 SUBJECT: Konus-Wind detection of the intermediate flare from SGR 1935+2154 DATE: 21/12/28 15:49:02 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The very bright burst from SGR 1935+2154 (AGILE observations: Ursi et al., GCN Circ. 31296; Swift-BAT detection: Palmer et al., ATel #15141) triggered Konus-Wind at T0=13350.516 s UT (03:42:30.516) on 2021 December 24. The light curve shows a single pulse with a sharp(<10 ms) rise and a total duration of ~1.3 s. The emission is seen up to ~250 keV The Konus-Wind light curve of this SGR is available at http://www.ioffe.ru/LEA/SGRs/211224_T13350/ As observed by Konus-Wind, the burst had a fluence of 1.09(-0.02,+0.02)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.640 s, of 1.33(-0.09,+0.09)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+8.448 s) is best fit in the 20 - 250 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.32(-0.26,+0.27) and Ep = 36(-1,+1) keV (chi2 = 35/29 dof). The 2BB fit to this spectrum yields the cool BB temperature kT1 = 5.2 (-1.5,+1.9) keV and the hot BB temperature kT2 = 11.3 (-0.6,+1.3) keV (chi2=37/28 dof). The rather long duration of the burst along with the large measured energy fluence put the burst in the class of "intermediate" SGR bursts. Among 43 bright bursts from SGR 1935+2154 detected by KW so far this event is the fourth most fluent. The measured spectral parameters are in typical range for bright short and intermediate SGR bursts. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31396 SUBJECT: GECAM detection of a short burst from SGR 1935+2154 DATE: 22/01/06 15:29:12 GMT FROM: Y Q Zhang at IHEP Y. Q. Zhang, S. L. Xiong, C. Cai, S. Xiao, P. Zhang, C. Y. Li, S. L. Xie, X. Y. Zhao, Y. Huang, X. Y. Song, J. C. Liu, Y. Zhao, Z. W. Guo, C. Zheng, W. C. Xue, C. W. Wang, Q. B. Yi, B. X. Zhang, W. X. Peng, R. Qiao, D. Y. Guo, X. B. Li, X. Ma, L. M. Song, P. Wang, J. Wang, Z. Zhang, S. J. Zheng, W. Chen, J. J. He, G. Y. Zhao, Y. Q. Du, H. Wu, J. Liang, Q. Luo, X. L. Zhang, H. M. Zhang, Z. H. An, M. Gao, K. Gong, B. Li, C. Li, J. H. Li, X. Q. Li, Y. G. Li, X. H. Liang, X. J. Liu, Y. Q. Liu, X. L. Sun, Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, X. Zhou, F. J. Lu, S. N. Zhang (IHEP) report on behalf of GECAM team: During the commissioning phase, GECAM-B was triggered in-flight by a short burst (trig# 95135774) at 2022-01-06T02:36:14.100 UTC (T0). Its alert data was promptly downlinked to the ground through the short message service of BeiDou Navigation Satellite System (BDS). The time latency of the first BeiDou message relative to the trigger time is about 1 minute. According to the GECAM-B light curves in about 30-1020 keV, this burst mainly consists of a single pulse with a duration about 50 ms. The location is consistent with SGR J1935+2154 within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/gecamb_lc_grd_all_combine_95135774.png As the detailed science data are downloaded, all analyses would be improved. Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31444 SUBJECT: AGILE observations of a burst from SGR 1935+2154 DATE: 22/01/12 16:42:13 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), C. Pittori, F. Verrecchia (SSDC, and INAF/OAR), M. Cardillo (INAF/IAPS), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, E. Menegoni, L. Foffano, L. Pacciani, G. Piano (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, F. Fuschino, N. Parmiggiani, V. Fioretti (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), F. Longo (Univ. Trieste and INFN Trieste), A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite detected a short burst at T0 = 2022-01-12 08:39:25 (UTC), compatible with the fourth bright burst from the SGR1935+2154 recently reported by GECAM (GCN #31443). The event is clearly visible in the AGILE scientific ratemeters of the SuperAGILE (SA; 20-60 keV) and AntiCoincidence (AC; 50-200 keV) detectors. The burst released a total number of 117 counts in the SA detector (above a background rate of 100 Hz), and 4938 counts in the AC detector (above a background rate of 3575 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/SGR220112_AGILE_RM.png . Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31497 SUBJECT: Konus-Wind observation of the recent SGR 1935+2154 activity DATE: 22/01/19 13:46:08 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: Since the last KW GCN on the ongoing SGR 1935+2154 activity (Ridnaia et al., GCN 31325) the instrument triggered on thirteen bright bursts from the source. The following is a list of the Konus-Wind triggers. --------------------------------------------- # Date T0(KW) s UT --------------------------------------------- 1 20211229 60082.391 s UT (16:41:22.391) 2 20220111 61551.690 s UT (17:05:51.690) 3 20220112 31161.806 s UT (08:39:21.806) 4 20220113 29375.444 s UT (08:09:35.444) 5 20220113 46378.912 s UT (12:52:58.912) 6 20220113 80750.270 s UT (22:25:50.270) 7 20220114 33622.126 s UT (09:20:22.126) 8 20220114 58119.186 s UT (16:08:39.186) 9 20220114 71808.322 s UT (19:56:48.322) 10 20220115 30352.115 s UT (08:25:52.115) 11 20220115 62515.176 s UT (17:21:55.176) 12 20220115 70649.225 s UT (19:37:29.225) 13 20220116 50974.968 s UT (14:09:34.968) --------------------------------------------- The bursts have durations (~0.2-0.9 s), energy fluences (0.9-5.9)x10^-6 erg/cm2, and spectral hardness (Ep ~ 20-45 keV) typical of bright short bursts from SGR 1935+2154 observed by KW previously. The detailed analysis of these bursts will be presented in the dedicated paper. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31512 SUBJECT: IPN triangulation of a bright burst from SGR 1935+2154 DATE: 22/01/21 16:19:14 GMT FROM: Dmitry Svinkin at Ioffe Institute A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey teams, D. Svinkin, A. Ridnaia, D. Frederiks, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo, and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, and R. Starr, on behalf of the GRS-Odyssey GRB team, report: A very bright, short-duration, soft burst has been detected by Konus-Wind, INTEGRAL (SPI-ACS), and Mars-Odyssey (HEND), so far, at about 35470 s UT (09:51:10). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 293.659 (19h 34m 38s) +21.934 (+21d 56' 03") Corners: 293.077 (19h 32m 18s) +22.236 (+22d 14' 11") 293.139 (19h 32m 33s) +22.259 (+22d 15' 34") 294.235 (19h 36m 56s) +21.626 (+21d 37' 33") 294.173 (19h 36m 41s) +21.604 (+21d 36' 15") --------------------------------------------- The error box area is 213 sq. arcmin, and its maximum dimension is 74 arcmin (the minimum one is 5 arcmin). The Sun distance was 44 deg. This box may be improved. The position of SGR 1935+2154 is inside the box at 4.6 arcmin from the box center. Given the positional coincidence of this burst with SGR 1935+2154, its time history, and softness of its spectrum (as observed by Konus-Wind), we conclude this burst is likely originated from SGR 1935+2154. A triangulation map is posted at http://www.ioffe.ru/LEA/SGRs/220120_T35475/IPN/ The time history and spectrum will be given in forthcoming GCN Circulars. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31513 SUBJECT: Konus-Wind detection of an intermediate flare from SGR 1935+2154 on January 20 DATE: 22/01/21 16:42:21 GMT FROM: Anna Ridnaia at Ioffe Institute A. Ridnaia, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The bright burst from SGR 1935+2154 (IPN triangulation: Kozyrev et al., GCN Circ. 31512) triggered Konus-Wind at T0=35475.962 s UT (09:51:15.962) on 2021 January 20. The light curve shows a single pulse with a sharp(<10 ms) rise and a total duration of ~1.2 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/220120_T35475/ As observed by Konus-Wind, the burst had a fluence of 7.54(-0.19,+0.19)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0+0.012 s, of 1.08(-0.11,+0.11)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+1.024 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.17(-0.26,+0.27) and Ep = 43(-1,+1) keV (chi2 = 44/25 dof). The rather long duration of the event along with the large measured energy fluence put the burst in the class of "intermediate" SGR flares. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31515 SUBJECT: AGILE observations of a bright burst from SGR 1935+2154 DATE: 22/01/21 18:57:44 GMT FROM: Alessandro Ursi at INAF/IAPS A. Ursi (INAF/IAPS), F. Longo (Univ. Trieste and INFN Trieste), F. Verrecchia, C. Pittori (SSDC, and INAF/OAR), M. Tavani (INAF/IAPS, and Univ. Roma Tor Vergata), A. Argan, M. Cardillo, C. Casentini, Y. Evangelista, E. Menegoni, L. Foffano, L. Pacciani, G. Piano, M. Romani (INAF/IAPS), F. Lucarelli (SSDC, and INAF/OAR), A. Bulgarelli, V. Fioretti, F. Fuschino, N. Parmiggiani (INAF/OAS-Bologna), M. Marisaldi (INAF/OAS-Bologna, and Bergen University), M. Pilia, A. Trois (INAF/OA-Cagliari), I. Donnarumma (ASI), , A. Giuliani (INAF/IASF-Mi), report on behalf of the AGILE Team: The AGILE satellite clearly detected the bright burst from the SGR1935+2154, at T0 = 2022-01-20 09:51:16 s (UTC), reported by Konus-Wind (GCN #31513) and triangulated by IPN (GCN #31512). The burst is clearly visible in the AGILE scientific ratemeters of the SuperAGILE detector (SA; 20-60 keV) and in all the five panels of the AntiCoincidence system (AC Top, 50-200 keV; AC Lat, 80-200 keV). The event released a total number of 289 counts in the SA detector (above a background rate of 115 Hz), and 5100 counts in the AC detector (above a background rate of 3400 Hz). The AGILE ratemeter light curves can be found at http://www.agilescienceapp.it/notices/SGR1935+2154_220120_AGILE_RM.png . At T0, the SGR1935+2154 was 110 deg off-axis for AGILE. Additional analysis of AGILE data is in progress. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32126 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25 DATE: 22/05/26 16:32:21 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A short, soft, SGR-like burst triggered Konus-Wind on 2022 May 25 at T0=25816.58 s UT (07:10:16.580). The Konus-Wind ecliptic latitude response is consistent with the SGR 1935+2154 position. So, taking in account the ongoing bursting activity of this source, burst time history, and softness of its spectrum (as observed by Konus-Wind), we suggest that this burst is likely a SGR flare originated from SGR 1935+2154. The burst light curve shows a single pulse started at ~T0-72 ms with a total duration of ~194 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/220525_T25816/ As observed by Konus-Wind, the burst had a fluence of 2.55(-0.10,+0.10)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.014 s, of 2.08(-0.16,+0.16)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The spectrum of the burst (measured from T0 to T0+0.192 s) is best fit in the 20 - 200 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.22(-0.54,+0.61) and Ep = 36(-3,+2) keV (chi2 = 20/18 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32204 SUBJECT: Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16 DATE: 22/06/17 12:45:28 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The bright burst from SGR 1935+2154 triggered Konus-Wind at T0=25915.887 s UT (07:11:55.887) on 2022 June 16. The light curve shows a single pulse with a sharp(<10 ms) rise and a total duration of ~0.8 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/220616_T25915/ As observed by Konus-Wind, the burst had a fluence of 1.15(-0.03,+0.03)x10^-5 erg/cm2, and a 16-ms peak flux, measured from T0+0.070 s, of 2.32(-0.16,+0.16)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+0.256 s) is best fit in the 20 - 500 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.35(-0.26,+0.28) and Ep = 39(-2,+2) keV (chi2 = 17/22 dof). The rather long duration of the burst along with the large measured energy fluence put the burst in the class of "intermediate" SGR bursts. Among 61 bright bursts from SGR 1935+2154 detected by KW so far this event is the fourth most fluent. The measured spectral parameters are in typical range for bright short and intermediate SGR bursts. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32737 SUBJECT: Fermi Gamma-ray Burst Monitor continues to detect SGR 1935+2154 DATE: 22/10/13 15:03:24 GMT FROM: Christian Malacaria at ISSI C. Malacaria (ISSI), P. Veres (UAH) and O. Roberts (USRA) report on behalf of the Fermi-GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 221013391/687345829 at 09:23:44.18 UT, 221013376/687344475 at 09:01:10.88 UT, 221013334/687340841 at 08:00:36.49 UT, 221013304/687338292 at 07:18:07.15 UT, 221013295/687337536 at 07:05:31.76 UT, 221013037/687315163 at 00:52:38.25 UT on 13 October 2022 and 221012977/687310007 at 23:26:42.31 UT, 221012906/687303863 at 21:44:18.47 UT, 221012874/687301134 at 20:58:49.99 UT, 221012773/687292428 at 18:33:43.51 UT, 221012709/687286852 at 17:00:47.29 UT, on 12 October 2022 all tentatively classified as a GRB, are in fact not due to a GRB. These triggers are due to a SGR 1935+2154 which, as recently announced (Mereghetti et al., GCN #32706 and Roberts et al. GCN #32708), is undergoing high bursting activity. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32764 SUBJECT: Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154 DATE: 22/10/15 16:23:09 GMT FROM: Peter Veres at UAH P. Veres (UAH), S. Lesage (UAH) and C. Malacaria (ISSI) report on behalf of the Fermi-GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 221013599/687363763 at 14:22:38.10, 221013646/687367836 at 15:30:31.54, 221013862/687386508 at 20:41:43.00, on 13 October 2022 and 221014098/687406838 at 02:20:33.52, 221014238/687418940 at 05:42:15.46, 221014300/687424353 at 07:12:28.77, 221014309/687425087 at 07:24:42.11, 221014487/687440524 at 11:41:59.73, 221014521/687443446 at 12:30:41.22, 221014556/687446436 at 13:20:31.77, 221014579/687448456 at 13:54:11.01, 221014711/687459861 at 17:04:16.62, 221014719/687460494 at 17:14:49.05 on 14 October 2022 all tentatively classified as a GRB, are in fact not due to a GRB. These triggers are due to a SGR 1935+2154 which, as recently announced (Mereghetti et al., GCN #32706 and Roberts et al. GCN #32708), is undergoing high bursting activity. For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32768 SUBJECT: Konus-Wind observation of the recent SGR 1935+2154 activity DATE: 22/10/16 06:19:56 GMT FROM: Anna Ridnaia at Ioffe Institute Since the last KW GCN on the ongoing SGR 1935+2154 activity (Ridnaia et al., GCN 32204) the instrument triggered on six bright bursts from the source. The following is a list of the Konus-Wind triggers with preliminary estimates of the burst fluences and peak fluxes. ------------------------------------------------------------------ # Date T0(KW) s UT Fl* PF** ------------------------------------------------------------------ 1 20221012 56552.646 s UT(15:42:32.646) 3.09 +/-0.10 15.2 +/-1.3 2 20221013 7366.180 s UT(02:02:46.180) 3.30 +/-0.11 16.9 +/-1.4 3 20221013 81690.645 s UT(22:41:30.645) 5.75 +/-0.22 19.6 +/-1.5 4 20221014 25949.934 s UT(07:12:29.934) 1.92 +/-0.08 16.0 +/-1.5 5 20221014 50052.142 s UT(13:54:12.142) 0.71 +/-0.06 14.7 +/-1.8 6 20221014 61721.260 s UT(17:08:41.260) 1.88 +/-0.18 20.3 +/-2.4 ------------------------------------------------------------------ * - Fluence (20-500 keV) in units of 1e-6 erg/cm2 ** - Peak Flux (20-500 keV) on 16-ms time scale in units of 1e-6 erg/cm2/s The time-averaged spectra of the bursts are well fit in the 20 - 500 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters: ------------------------------------------------------------------ # T100 Tbeg-Tend alpha Ep(keV) chi2/dof ------------------------------------------------------------------ 1 0.434 0 - 0.256 0.54(-0.61,+0.68) 29(-3,+2) 12/19 2 0.330 0 - 0.256 -0.20(-0.38,+0.41) 33(-3,+2) 24/20 3 0.424 0 - 8.448 -0.05(-0.38,+0.41) 39(-2,+2) 48/40 4 0.202 0 - 0.192 -1.00(-0.48,+0.54) 27(-8,+5) 20/20 5 0.168 0 - 0.128 -0.5 fixed 25(-3,+4) 13/16 6 0.516 0 - 8.448 -1.36(-0.62,+1.29) 17(-10,+11) 48/40 ------------------------------------------------------------------ The emission in all bursts is seen up to ~200 keV. The Konus-Wind light curves of the bursts are available at http://www.ioffe.ru/LEA/SGRs/221012_T56552/ http://www.ioffe.ru/LEA/SGRs/221013_T07366/ http://www.ioffe.ru/LEA/SGRs/221013_T81690/ http://www.ioffe.ru/LEA/SGRs/221014_T25949/ http://www.ioffe.ru/LEA/SGRs/221014_T50052/ http://www.ioffe.ru/LEA/SGRs/221014_T61721/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32770 SUBJECT: Konus-Wind detection of a short burst coincident with a bright radio burst from SGR 1935+2154 DATE: 22/10/16 16:01:29 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, A. Ridnaia, D. Svinkin, A. Lysenko, M. Ulanov (all - Ioffe Institute), and A. Tsvetkova (Ioffe Institute/University of Cagliari), report: Konus-Wind (KW) detected a short X-ray burst on 2022-10-14 in time interval from 19:21:39.205 UTC to 19:21:42.149 UTC. Corrected for the propagation from low-Earth orbit to Wind (~1.05 s), the burst arrival time is consistent with the detection time of a bright short X-ray burst from SGR 1935+2154, reported by GECAM and HEBS (Atel #15682), which, in turn, is consistent with the dedispersed topocentric time of a bright radio burst detected from SGR 1935+2154 by CHIME (Atel #15681). The event was detected by KW in the waiting mode and no detailed information on its temporal structure is available. The emission is seen in two instrument's energy bands: G1(20-80 keV) and G2 (80-320 keV), while no statistically significant signal is visible above 320 keV. A time-averaged spectrum of the burst can be described in the 20-1300 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the peak energy Ep of (40 ± 6) keV, which is slightly higher than a typical Ep of multiple bright SGR 1935+2154 bursts detected by KW recently (GCN Circ. 32768). We also note that the October 14 burst Ep is about twice as lower as the peak energy (~85 keV) measured by KW for the much radio-brighter event SGR/FRB200428 from the same magnetar (Ridnaia et al. 2021, NatAstr. 5, 372). From the KW detection, we estimate the total 20-500 keV fluence of the burst to (5.7 ± 0.6)x10^-7 erg/cm2, about two times lower than that of SGR/FRB200428. This GCN circular duplicates ATel #15686. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32792 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17 DATE: 22/10/18 14:35:09 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A short, soft, SGR-like burst triggered Konus-Wind on 2022 October 17 at T0=40483.010 s UT (11:14:43.010). The Konus-Wind ecliptic latitude response is consistent with the SGR 1935+2154 position. So, taking in account the ongoing bursting activity of this source, burst time history, and softness of its spectrum (as observed by Konus-Wind), we suggest that this burst is likely a SGR flare originated from SGR 1935+2154. The burst light curve shows a single pulse started at ~T0-56 ms with a total duration of ~202 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/221017_T40483/ As observed by Konus-Wind, the burst had a fluence of 2.16(-0.10,+0.10)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.006 s, of 2.84(-0.22,+0.22)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The spectrum of the burst (measured from T0 to T0+0.192 s) is best fit in the 20 - 500 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.71(-0.50,+0.57) and Ep = 33(-7,+5) keV (chi2 = 15/19 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32794 SUBJECT: SGR 1935+2154: Detection by GRBAlpha DATE: 22/10/18 15:13:13 GMT FROM: Marianna Dafcikova at Masaryk University <500025@mail.muni.cz> M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), F. Munz, N. Husarikova, J.-P. Breuer, M. Topinka, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropoli tan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The recently active SGR 1935+2154 (Fermi-GBM detection: Veres et al., GCN 32764, Konus-Wind detection: Ridnaia et al., GCN 32768) was detected by the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020). This is the first time an SGR was detected by GRBAlpha. The 11 sigma detection was confirmed at the peak time 2022-10-14 07:12:27.8 UTC. The temporal resolution of the observation was 4 s and the light curve obtained by GRBAlpha shows an excess in one bin. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/SGR1935+2154_GCN.pdf GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Its detector consists of a 75 x 75 x 5 mm^3 CsI(Tl) scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, we are continuously upgrading the on-board data acquisition software stack. The ground segment is also supported by the radio amateur community, and it takes advantage of the SatNOGS network for increased data downlink volume. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32797 SUBJECT: SGR 1935+2154: Bursting activity detected by VZLUSAT-2 DATE: 22/10/18 22:39:15 GMT FROM: Jakub Ripa at Masaryk University <245487@mail.muni.cz> J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N. Werner (Masaryk U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz, M. Dafcikova, N. Husarikova, M. Topinka, F. Hroch, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU)  -- the VZLUSAT-2/GRB payload collaboration. The recently active SGR 1935+2154 (Fermi-GBM detection: Malacaria et al., GCN Circ. 32737, Konus-Wind detection: Ridnaia et al., GCN Circ. 32768) was detected by the GRB detector module no. 1 on board of the VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/). The list of detected SGR bursts with their significance is: Date and time in UTC     SNR 2022-10-12 23:26:41      17.6 2022-10-13 02:02:43      16.5 2022-10-13 22:41:28      125 The light curves obtained by VZLUSAT-2 are available here: https://vzlusat2.konkoly.hu/static/share/SGR_1935_2154_GCN_VZLUSAT-2.pdf GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSats constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32814 SUBJECT: SGR 1935+21542: VZLUSAT-2 and GRBAlpha joint detection DATE: 22/10/21 21:59:38 GMT FROM: Jakub Ripa at Masaryk University <245487@mail.muni.cz> J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N. Werner  (Masaryk U.), M. Ohno (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz, M. Dafcikova, N. Husarikova, M. Topinka, F. Hroch, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Poon, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU), T. Urbanec, M. Kasal, A. Povalac (Brno U. of Technology), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), T. Bozoki, G. Dalya, G. Friss, K. Kapas, J. Takatsy (Eotvos U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the VZLUSAT-2/GRB payload and GRBAlpha collaborations We report a joint detection of the recently active SGR 1935+2154 by the GRB detector on board of VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/) and 1U GRBAlpha CubeSat (Pal et al. Proc. SPIE 2020). The bursting activity was also observed by Insight-HXMT (C. K. Li et al., ATel #15698), INTEGRAL/SPI-ACS, and  Konus-Wind (D. Svinkin priv. comm.). Non-detection by Fermi/GBM can be explained by the Earth occultation of  SGR 1935+2154 (P. Veres priv. comm.). The list of distinct peaks measured by the GRB detector module no. 1 on board of the VZLUSAT-2 with their background-subtracted peak rates in ~40-890 keV band and significance is: Date and time in UTC     peak rate (cnt/s)      SNR 2022-10-14 17:26:07.5                  220     12.9 2022-10-14 17:27:36.5                 1170     62.6 2022-10-14 17:27:39.5                  931     48.8 2022-10-14 17:27:43.5                  159      8.1 2022-10-14 17:27:49.5                  205     10.0 The light curves obtained by VZLUSAT-2 and GRBAlpha are available here: https://grbalpha.konkoly.hu/static/share/SGR_1935_2154_GCN_GRBAlpha_VZLUSAT_2.pdf GRB detectors on VZLUSAT-2 are a demonstration payload for a future CubeSats constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13 from Cape Canaveral. GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). Its detector consists of a 75 x 75 x 5 mm^3 CsI(Tl) scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, we are continuously upgrading the on-board data acquisition software stack. The ground segment is also supported by the radio amateur community, and it takes advantage of the SatNOGS network for increased data downlink volume. We thank P. Veres and D. Svinkin for providing us with information which helped us to associate our detection with SGR 1935+2154. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32832 SUBJECT: Fermi Gamma-ray Burst Monitor detections of SGR 1935+2154 DATE: 22/10/24 18:13:28 GMT FROM: Peter Veres at UAH P. Veres (UAH) reports on behalf of the Fermi-GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) triggers 221015093/687492839 at 02:13:54.55, on 15 October 2022 and 221017553/687705349 at 13:15:44.21 on 17 October 2022 all tentatively classified as a GRB, are in fact not due to a GRB. These triggers are due to SGR 1935+2154 which recently underwent a period of high bursting activity (Mereghetti et al., GCN #32706 and Roberts et al. GCN #32708) For Fermi GBM data and information, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32855 SUBJECT: SGR 1935+2154: AstroSat CZTI Detections DATE: 22/10/26 15:13:06 GMT FROM: Gaurav Waratkar at IIT,Bombay G. Waratkar (IITB), V. Bhalerao (IITB), A. Vibhute (IUCAA), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of bursts from SGR 1935+2154 as follows. -------------------------------------------------------------------- Time | Detected_by | GCN -------------------------------------------------------------------- 2022-10-12T15:14:04.13 | Fermi-GBM | 32708 2022-10-14T13:20:31.77 | Fermi-GBM | 32764 -------------------------------------------------------------------- We also report a forest of seven bright bursts within 15s from 2022-10-14T17:27:33, that are likely related to SGR 1935+2154. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32938 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2022 November 9 DATE: 22/11/14 13:40:49 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The bright burst from SGR 1935+2154 (Fermi-GBM detection: Wood, GCN Circ. 32922) triggered Konus-Wind at T0=57968.083 s UT (16:06:08.083) on 2022 November 9. The burst light curve shows a bright pulse which starts at ~T0-0.246 s and has a duration of ~0.4 s. The main pulse is followed, after a short period of quiescence, by multiple weaker pulses in the interval from ~T0+0.6 s to ~T0+1.3 s. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/221109_T57968/ As observed by Konus-Wind, the burst had a fluence of 2.37(-0.11,+0.11)x10^-6 erg/cm2, and a 16-ms peak flux, measured from T0-0.064 s, of 1.35(-0.14,+0.14)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The spectrum of the burst (measured from T0 to T0+0.192 s) is best fit in the 20 - 500 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.02(-0.82,+0.92) and Ep = 28(-6,+4) keV (chi2 = 29/17 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 33051 SUBJECT: Konus-Wind detection of a burst from SGR 1935+2154 on 2022 December 13 DATE: 22/12/13 20:54:35 GMT FROM: Anna Ridnaia at Ioffe Institute A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: A bright burst from SGR 1935+2154 (also detected by Fermi-GBM (trigger 692607435) and GECAM (both reported in GCN Notices)) triggered Konus-Wind at T0=25026.883 s UT (06:57:06.883) on 2022 December 13. The burst light curve shows a bright pulse, which starts at ~T0-96 ms and has a total duration of ~142 ms. The emission is seen up to ~200 keV. The Konus-Wind light curve of this burst is available at http://www.ioffe.ru/LEA/SGRs/221213_T25026/ As observed by Konus-Wind, the burst had a fluence of 6.61(-0.48,+0.48)x10^-7 erg/cm2, and a 16-ms peak flux, measured from T0-0.012 s, of 1.31(-0.16,+0.16)x10^-5 erg/cm2/s (both in the 20 - 500 keV energy range). The spectrum of the burst (measured from T0 to T0+0.064 s) is best fit in the 20 - 500 keV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = 0.12(-1.06,+1.30) and Ep = 37(-8,+4) keV (chi2 = 15/11 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.