//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32112 SUBJECT: GRB 220525A: Fermi GBM Final Real-time Localization DATE: 22/05/25 00:21:19 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220525A (trigger 675130259.241452 / 220525008). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 14.9, Dec = 18.3 (J2000 degrees, equivalent to J2000 00h 59m, 18d 18'), with a statistical uncertainty of 1.2 degrees. The angle from the Fermi LAT boresight is 58.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_skymap_all_bn220525008.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_healpix_all_bn220525008.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32113 SUBJECT: GRB 220525A: BALROG localization (Fermi Trigger 675130259 / GRB 220525008) DATE: 22/05/25 00:32:54 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 675130259 at 00:10:54 on 25 May. 2022 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) = 10.61+/-1.03 deg Decl.(2000.0) = 15.31+/-0.70 deg We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB220525008/ The Healpix map can be downloaded from: https://grb.mpe.mpg.de/grb/GRB220525008/healpix The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB220525008/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32118 SUBJECT: IPN triangulation of GRB 220525A DATE: 22/05/25 21:48:51 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 team, D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, and C. Wilson-Hodge on behalf of the Fermi GBM team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 220525A (Fermi GBM detection: Fermi GBM Team, GCN Circ 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113) has been detected by Fermi (GBM trigger 675130259), CALET (CGBM), Konus-Wind, and Mars-Odyssey (HEND), so far, at about 654 s UT (00:10:54). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 13.365 (00h 53m 28s) +16.396 (+16d 23' 46") Corners: 17.561 (01h 10m 15s) +12.813 (+12d 48' 48") 9.561 (00h 38m 15s) +18.778 (+18d 46' 42") 9.753 (00h 39m 01s) +18.232 (+18d 13' 54") 18.017 (01h 12m 04s) +11.551 (+11d 33' 04") --------------------------------------------- The error box area is 4.2 sq. deg, and its maximum dimension is 10.9 deg (the minimum one is 25 arcmin). The Sun distance was 43 deg. This box may be improved. The IPN localization is consistent with, but reduces the area of, the Fermi GBM Final Real-time position (GCN Circ. 32112) and BALROG (GCN 32113) localizations. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB220525_T00654/IPN/ The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32119 SUBJECT: Fermi GRB 220525A: Global MASTER-Net observations report DATE: 22/05/26 11:15:29 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov, D.Cheryasov, Ya.Kechin (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev (Irkutsk State University, API), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich, V.Yurkov (Blagoveschensk Educational State University) MASTER-OAGH robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220525A ( Fermi GBM team, GCN 32112) errorbox 1 days 35557 sec after notice time and 1 days 35599 sec after trigger time at 2022-05-26 10:04:13 UT, with upper limit up to 17.2 mag. The observations began at zenith distance = 82 deg. The sun altitude is -24.1 deg. The galactic latitude b = -44 deg., longitude l = 126 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1984418 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 122089 | 2022-05-26 10:04:13 | MASTER-OAGH | (00h 59m 08.17s , +16d 24m 55.4s) | C | 180 | 15.5 | 122089 | 2022-05-26 10:04:13 | MASTER-OAGH | (00h 59m 38.00s , +16d 01m 05.6s) | C | 180 | 17.0 | 122701 | 2022-05-26 10:14:25 | MASTER-OAGH | (00h 59m 06.62s , +16d 25m 33.8s) | C | 180 | 16.1 | 122701 | 2022-05-26 10:14:25 | MASTER-OAGH | (00h 59m 35.09s , +16d 00m 35.7s) | C | 180 | 17.2 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32122 SUBJECT: Konus-Wind detection of GRB 220525A DATE: 22/05/26 12:36:42 GMT FROM: Dmitry Frederiks at Ioffe Institute D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long GRB 220525A (Fermi GBM detection: Fermi GBM Team, GCN 32112; BALROG localization: Kunzweiler et al., GCN 32113; IPN triangulation: Kozyrev et al., GCN 32118) triggered Konus-Wind (KW) at T0=654.268 s UT (00:10:54.268). The burst light curve shows a single multipeaked pulse, which starts at ~T0-3 s and has a total duration of ~12 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB220525_T00654/ As observed by Konus-Wind, the burst had a fluence of (1.7 ± 0.3)x10^-6 erg/cm^2 and a 64-ms peak energy flux, measured from T0 + 2.624 s, of (4.3 ± 0.7)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 15 MeV range by a Band function with the following model parameters: the low-energy photon index alpha = -0.69 (-0.22,+0.26), the high energy photon index beta = -3.0 (-7.0,+0.44), the peak energy Ep = 190 (-22,+26) keV, chi2 = 88/96 dof. All the quoted errors are estimated at the 90% confidence level. All the presented results are preliminary. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32125 SUBJECT: GRB 220525A: CALET Gamma-Ray Burst Monitor detection DATE: 22/05/26 14:54:18 GMT FROM: Yuta Kawakubo at Louisiana State U./CALET Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU), 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), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 220525A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113; IPN triangulation: Kozyrev et al., GCN Circ 32118; Konus-Wind detection: Frederiks et al., GCN Circ 32122) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 00:10:52.713 UTC on 25 May 2022 (http://cgbm.calet.jp/cgbm_trigger/flight/1337472486/index.html). The burst signal was seen by only SGM detector. The burst light curve shows a double-peaked structure which starts at T+1.6 sec, peaks at T+4.7 sec, and ends at T+8.7 sec. The T90 and T50 durations measured by the SGM data are 6.0 +/- 0.4 sec and 2.6 +/- 0.5 sec (40-1000 keV), respectively. The ground processed light curve is available at http://cgbm.calet.jp/cgbm_trigger/ground/1337472486/ The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at the Waseda University. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 32127 SUBJECT: GRB 220525A: Fermi GBM Detection DATE: 22/05/26 22:19:35 GMT FROM: Stephen Lesage at Fermi-GBM Team S. Lesage (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220525A (trigger 675130259/220525008) which was also detected by Konus-Wind (D. Frederiks et al. 2022, GCN 32122) and CALET (Y. Kawakubo et al. 2022, GCN 32125) and localized by IPN (Kozyrev et al. 2022, GCN 32118). The Fermi GBM Final Real-time Localization (GCN 32112) is consistent with the IPN triangulation. The angle from the Fermi LAT boresight is 58 degrees. The GBM light curve shows a single bright emission episode with a duration (T90) of about 16.1 s (10-1000 keV). The time-averaged spectrum from T0-10 to T0+15 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.12 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 176 +/- 10 keV. The event fluence (10-1000 keV) in this time interval is (1.45 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.7 s in the 10-1000 keV band is 15.4 +/- 0.3 ph/s/cm^2. 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/"