//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30600 SUBJECT: GRB 210807A: Swift detection of a burst with an optical counterpart DATE: 21/08/07 10:34:25 GMT FROM: David Palmer at LANL A. Y. Lien (GSFC/UMBC), C. Gronwall (PSU), J.D. Gropp (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 10:03:40 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210807A (trigger=1064221). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 76.677, +58.245 which is RA(J2000) = 05h 06m 43s Dec(J2000) = +58d 14' 43" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Because this is an image trigger, the actual light curve structure requires further ground data analysis. The 112-s image trigger indicates that this is a long burst. The XRT began observing the field at 10:07:02.3 UT, 201.9 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 76.6815, 58.2503 which is equivalent to: RA(J2000) = 05h 06m 43.56s Dec(J2000) = +58d 15' 01.1" with an uncertainty of 11.1 arcseconds (radius, 90% containment). This location is 20 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. The initial flux in the 2.5 s image was 4.08e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 210 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 05:06:43.90 = 76.68293 DEC(J2000) = +58:14:59.2 = 58.24978 with a 90%-confidence error radius of about 0.61 arc sec. This position is 3.3 arc sec. from the center of the XRT error circle. The estimated magnitude is 17.00 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.409. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30601 SUBJECT: GRB 210807B: Fermi GBM Final Real-time Localization DATE: 21/08/07 12:47:05 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 12:36:42 UT on 7 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210807B (trigger 650032607.844228 / 210807525). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 256.2, Dec = -32.2 (J2000 degrees, equivalent to J2000 17h 04m, -32d 12'), with a statistical uncertainty of 3.8 degrees. The angle from the Fermi LAT boresight is 19.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807525/quicklook/glg_skymap_all_bn210807525.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807525/quicklook/glg_healpix_all_bn210807525.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807525/quicklook/glg_lc_medres34_bn210807525.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30602 SUBJECT: GRB 210807A: BOOTES-5/JGT optical afterglow detection DATE: 21/08/07 14:09:06 GMT FROM: Youdong HU at IAA-CSIC Y.-D. Hu, T.-R. Sun, E. Fernandez-Garcia and A. J. Castro-Tirado, M.D. Caballero-Garcia (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar and I. Carrasco (UMA), I. H. Park (SKKU) on behalf of a larger collaboration, report: The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically responded in 16 min to the Swift trigger of GRB 210807A (Lien et al., GCNC 30600). The first image (1s exposure, clear-filter) was obtained at 10:20:19.5 UT. We detected the optical afterglow at the position reported by Swift /UVOT (Lien et al. GCNC 30600). In the co-added image (10 x 1s exposures) we measure 17.8+/- 0.2 mag. Further analysis is ongoing. The magnitude is calibrated against the USNO-B1 catalog and is not corrected for Galactic extinction in the direction towards the GRB. We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for its excellent support. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30603 SUBJECT: GRB 210807A: Enhanced Swift-XRT position DATE: 21/08/07 16:09:23 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1337 s of XRT Photon Counting mode data and 4 UVOT images for GRB 210807A, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 76.68376, +58.24980 which is equivalent to: RA (J2000): 05h 06m 44.10s Dec (J2000): +58d 14' 59.3" with an uncertainty of 2.1 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30605 SUBJECT: Swift GRB210807.78: Global MASTER-Net observations report DATE: 21/08/07 19:11:19 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, D. Cheryasov (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, 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB210807.78 (trigger No 1064377,16h 20m 31.75s , -15d 53m 51.4s, R=0.05) errorbox 12 sec after notice time and 153 sec after trigger time at 2021-08-07 18:44:14 UT, with upper limit up to 18.5 mag. The observations began at zenith distance = 20 deg. The sun altitude is -33.7 deg. The galactic latitude b = 23 deg., longitude l = 359 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683617 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 169 | MASTER-SAAO | P\ | 30 | 17.0 | 215 | MASTER-SAAO | P\ | 40 | 18.3 | 274 | MASTER-SAAO | P\ | 50 | 18.5 | The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30606 SUBJECT: Swift GRB210807.79: Global MASTER-Net observations report DATE: 21/08/07 19:41:16 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, D. Cheryasov (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, 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB210807.79 (trigger No 1064380,16h 20m 27.48s , -15d 56m 11.4s, R=0.05) errorbox 74 sec after notice time and 155 sec after trigger time at 2021-08-07 18:54:15 UT, with upper limit up to 16.8 mag. The observations began at zenith distance = 66 deg. The sun altitude is -17.8 deg. The galactic latitude b = 23 deg., longitude l = 359 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683622 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 170 | MASTER-Tavrida | P\ | 30 | 13.9 | 225 | MASTER-Tavrida | P\ | 40 | 14.0 | 289 | MASTER-Tavrida | P\ | 50 | 14.7 | 363 | MASTER-Tavrida | P\ | 60 | 14.4 | 452 | MASTER-Tavrida | P\ | 80 | 14.7 | 561 | MASTER-Tavrida | P\ | 100 | 14.7 | 929 | MASTER-Tavrida | C | 180 | 16.8 | 1366 | MASTER-Tavrida | C | 180 | 16.1 | 1802 | MASTER-Tavrida | C | 180 | 16.2 | 2541 | MASTER-Tavrida | C | 180 | 16.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30607 SUBJECT: Swift GRB 210807A: Global MASTER-Net observations report DATE: 21/08/07 20:08:23 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, D. Cheryasov (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, 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-Tavrida robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the Swift GRB 210807A ( A. Y. Lien et al., GCN 30600) errorbox 32639 sec after notice time and 33871 sec after trigger time at 2021-08-07 19:28:12 UT, with upper limit up to 16.6 mag. The observations began at zenith distance = 76 deg. The sun altitude is -21.7 deg. The galactic latitude b = 11 deg., longitude l = 152 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683291 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 33962 | MASTER-Tavrida | C | 180 | 13.4 | 35859 | MASTER-Tavrida | C | 180 | 16.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30608 SUBJECT: Fermi GRB 210807B: Global MASTER-Net observations report DATE: 21/08/07 21:30:37 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, D. Cheryasov (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, 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) started inspect of the Fermi GRB 210807B ( Fermi GBM team, GCN 30601) errorbox 28908 sec after notice time and 28937 sec after trigger time at 2021-08-07 20:38:59 UT, with upper limit up to 18.0 mag. Observations started at twilight. The observations began at zenith distance = 60 deg. The sun altitude is -11.2 deg. The galactic latitude b = 5 deg., longitude l = 353 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683395 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 28967 | 2021-08-07 20:38:59 | MASTER-IAC | (17h 12m 56.82s , -31d 05m 11.5s) | C | 60 | 16.1 | 28967 | 2021-08-07 20:38:59 | MASTER-IAC | (17h 03m 35.72s , -30d 59m 44.0s) | C | 60 | 16.0 | 29047 | 2021-08-07 20:40:20 | MASTER-IAC | (17h 16m 35.97s , -33d 00m 24.9s) | C | 60 | 16.6 | 29047 | 2021-08-07 20:40:20 | MASTER-IAC | (17h 07m 03.20s , -32d 54m 57.0s) | C | 60 | 16.1 | 29127 | 2021-08-07 20:41:40 | MASTER-IAC | (16h 48m 51.47s , -32d 55m 34.2s) | C | 60 | 16.6 | 29127 | 2021-08-07 20:41:40 | MASTER-IAC | (16h 58m 24.29s , -33d 01m 02.3s) | C | 60 | 16.5 | 29207 | 2021-08-07 20:43:00 | MASTER-IAC | (17h 10m 44.02s , -29d 13m 03.7s) | C | 60 | 16.7 | 29207 | 2021-08-07 20:43:00 | MASTER-IAC | (17h 01m 33.44s , -29d 07m 34.1s) | C | 60 | 16.6 | 29288 | 2021-08-07 20:44:20 | MASTER-IAC | (17h 02m 55.00s , -34d 53m 40.6s) | C | 60 | 16.8 | 29288 | 2021-08-07 20:44:20 | MASTER-IAC | (16h 53m 09.59s , -34d 48m 12.6s) | C | 60 | 16.7 | 29368 | 2021-08-07 20:45:40 | MASTER-IAC | (16h 55m 14.70s , -31d 06m 37.7s) | C | 60 | 17.1 | 29368 | 2021-08-07 20:45:40 | MASTER-IAC | (16h 45m 53.53s , -31d 01m 08.2s) | C | 60 | 17.0 | 29448 | 2021-08-07 20:47:00 | MASTER-IAC | (17h 21m 30.81s , -34d 54m 09.6s) | C | 60 | 18.0 | 29448 | 2021-08-07 20:47:00 | MASTER-IAC | (17h 11m 45.36s , -34d 48m 40.7s) | C | 60 | 17.3 | 29528 | 2021-08-07 20:48:21 | MASTER-IAC | (16h 53m 13.33s , -29d 12m 07.3s) | C | 60 | 17.1 | 29528 | 2021-08-07 20:48:21 | MASTER-IAC | (16h 44m 02.70s , -29d 06m 37.9s) | C | 60 | 17.3 | 29608 | 2021-08-07 20:49:41 | MASTER-IAC | (17h 09m 31.78s , -27d 17m 33.2s) | C | 60 | 17.2 | 29608 | 2021-08-07 20:49:41 | MASTER-IAC | (17h 00m 30.73s , -27d 12m 02.9s) | C | 60 | 16.9 | 29688 | 2021-08-07 20:51:00 | MASTER-IAC | (17h 30m 47.18s , -31d 07m 06.4s) | C | 60 | 17.6 | 29688 | 2021-08-07 20:51:00 | MASTER-IAC | (17h 21m 25.82s , -31d 01m 36.5s) | C | 60 | 17.1 | 29768 | 2021-08-07 20:52:20 | MASTER-IAC | (17h 08m 42.53s , -36d 49m 32.2s) | C | 60 | 17.8 | 29768 | 2021-08-07 20:52:20 | MASTER-IAC | (16h 58m 42.55s , -36d 44m 04.1s) | C | 60 | 17.0 | 29848 | 2021-08-07 20:53:40 | MASTER-IAC | (17h 28m 08.83s , -29d 13m 52.9s) | C | 60 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30609 SUBJECT: GRB 210807C: Fermi GBM Final Real-time Localization DATE: 21/08/07 23:05:39 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 22:55:24 UT on 7 Aug 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210807C (trigger 650069729.307352 / 210807955). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 147.6, Dec = -51.4 (J2000 degrees, equivalent to J2000 09h 50m, -51d 23'), with a statistical uncertainty of 1.7 degrees. The angle from the Fermi LAT boresight is 60.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807955/quicklook/glg_skymap_all_bn210807955.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807955/quicklook/glg_healpix_all_bn210807955.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210807955/quicklook/glg_lc_medres34_bn210807955.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30610 SUBJECT: GRB 210807C: Swift detection of a burst DATE: 21/08/07 23:14:05 GMT FROM: David Palmer at LANL A. Y. Lien (GSFC/UMBC), C. Gronwall (PSU), J.D. Gropp (PSU), N. J. Klingler (GSFC/UMBC/CRESSTII), K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 22:57:08 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 210807C (trigger=1064421). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 143.551, -51.409 which is RA(J2000) = 09h 34m 12s Dec(J2000) = -51d 24' 31" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). Although the lightcurve before T+8s is not currently available due to a telemetry dropout, the later lightcurve shows a complex structure extending at least to T+90s. The peak count rate in the available lightcurve was ~800 counts/sec (15-350 keV), at ~20 sec after the trigger. The XRT began observing the field at 23:00:05.5 UT, 177.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source located at RA, Dec 143.53455, -51.40237 which is equivalent to: RA(J2000) = 09h 34m 08.29s Dec(J2000) = -51d 24' 08.5" with an uncertainty of 7.1 arcseconds (radius, 90% containment). This location is 43 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. We cannot determine whether the source is fading at the present time. A power-law fit to a spectrum formed from promptly downlinked event data does not constrain the column density. The initial flux in the 2.5 s image was 2.31e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 250 seconds with the V filter starting 180 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of the XRT error circle. The typical 3-sigma upper limit has been about 19.2 mag. The 8'x8' region for the list of sources generated on-board covers 100% of the XRT error circle. The list of sources is typically complete to about 18.0 mag. No correction has been made for the large, but uncertain, extinction expected. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30611 SUBJECT: Swift GRB210807.96: Global MASTER-Net observations report DATE: 21/08/07 23:14:18 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, D. Cheryasov (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, 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB210807.96 (trigger No 1064421,09h 34m 12.24s , -51d 24m 32.4s, R=0.05) errorbox 55 sec after notice time and 171 sec after trigger time at 2021-08-07 22:59:59 UT, with upper limit up to 17.0 mag. Observations started at twilight. The observations began at zenith distance = 66 deg. The sun altitude is -12.4 deg. The galactic latitude b = 0 deg., longitude l = 275 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683851 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 181 | MASTER-OAFA | C | 20 | 16.6 | 226 | MASTER-OAFA | C | 30 | 16.8 | 280 | MASTER-OAFA | C | 40 | 17.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30612 SUBJECT: Fermi GRB 210807C: Global MASTER-Net observations report DATE: 21/08/08 03:30:32 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, D. Cheryasov (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, 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-OAFA robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 210807C ( Fermi GBM team, GCN 30609) errorbox 114 sec after notice time and 206 sec after trigger time at 2021-08-07 22:58:50 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenith distance = 64 deg. The sun altitude is -12.1 deg. MASTER-SAAO robotic telescope located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 210807C errorbox 15419 sec after notice time and 15511 sec after trigger time at 2021-08-08 03:13:56 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 81 deg. The sun altitude is -27.5 deg. The galactic latitude b = 2 deg., longitude l = 277 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683879 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 222 | 2021-08-07 22:58:50 | MASTER-OAFA | (09h 51m 36.60s , -48d 08m 16.7s) | C | 30 | 16.4 | 285 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.94s , -50d 38m 28.4s) | C | 20 | 16.6 | 320 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.95s , -50d 38m 28.4s) | C | 90 | 17.3 | Coadd 615 | 2021-08-07 22:59:59 | MASTER-OAFA | (09h 32m 30.93s , -50d 38m 28.5s) | C | 680 | 18.3 | Coadd 330 | 2021-08-07 23:00:39 | MASTER-OAFA | (09h 32m 26.75s , -50d 36m 58.8s) | C | 30 | 16.8 | 384 | 2021-08-07 23:01:28 | MASTER-OAFA | (09h 32m 26.54s , -50d 38m 17.9s) | C | 40 | 17.0 | 449 | 2021-08-07 23:02:28 | MASTER-OAFA | (09h 32m 28.68s , -50d 37m 04.2s) | C | 50 | 17.1 | 524 | 2021-08-07 23:02:28 | MASTER-OAFA | (09h 32m 28.68s , -50d 37m 04.3s) | C | 200 | 17.8 | Coadd 528 | 2021-08-07 23:03:37 | MASTER-OAFA | (09h 32m 22.55s , -50d 37m 43.5s) | C | 70 | 17.3 | 622 | 2021-08-07 23:05:06 | MASTER-OAFA | (09h 32m 22.46s , -50d 36m 42.4s) | C | 80 | 17.5 | 732 | 2021-08-07 23:06:46 | MASTER-OAFA | (09h 32m 28.12s , -50d 37m 41.4s) | C | 100 | 17.7 | 877 | 2021-08-07 23:06:46 | MASTER-OAFA | (09h 32m 28.14s , -50d 37m 41.5s) | C | 390 | 18.3 | Coadd 866 | 2021-08-07 23:08:45 | MASTER-OAFA | (09h 32m 22.16s , -50d 38m 40.7s) | C | 130 | 17.9 | 1030 | 2021-08-07 23:11:14 | MASTER-OAFA | (09h 32m 29.66s , -50d 38m 09.7s) | C | 160 | 18.0 | 1220 | 2021-08-07 23:14:14 | MASTER-OAFA | (09h 32m 25.67s , -50d 37m 04.8s) | C | 180 | 18.2 | 1400 | 2021-08-07 23:14:14 | MASTER-OAFA | (09h 32m 25.67s , -50d 37m 04.8s) | C | 540 | 18.6 | Coadd 1420 | 2021-08-07 23:17:34 | MASTER-OAFA | (09h 32m 25.60s , -50d 38m 34.9s) | C | 180 | 18.2 | 1619 | 2021-08-07 23:20:53 | MASTER-OAFA | (09h 32m 28.21s , -50d 36m 47.5s) | C | 180 | 18.3 | 1819 | 2021-08-07 23:24:13 | MASTER-OAFA | (09h 32m 22.92s , -50d 37m 36.2s) | C | 180 | 18.2 | 1999 | 2021-08-07 23:24:13 | MASTER-OAFA | (09h 32m 22.92s , -50d 37m 36.2s) | C | 540 | 18.6 | Coadd 2019 | 2021-08-07 23:27:32 | MASTER-OAFA | (09h 32m 22.25s , -50d 36m 35.5s) | C | 180 | 18.3 | 2218 | 2021-08-07 23:30:52 | MASTER-OAFA | (09h 32m 28.88s , -50d 37m 34.8s) | C | 180 | 18.3 | 2417 | 2021-08-07 23:34:11 | MASTER-OAFA | (09h 32m 22.28s , -50d 38m 34.3s) | C | 180 | 18.2 | 2597 | 2021-08-07 23:34:11 | MASTER-OAFA | (09h 32m 22.29s , -50d 38m 34.3s) | C | 540 | 18.6 | Coadd 2617 | 2021-08-07 23:37:31 | MASTER-OAFA | (09h 32m 29.11s , -50d 38m 18.2s) | C | 180 | 18.2 | 2816 | 2021-08-07 23:40:50 | MASTER-OAFA | (09h 32m 25.11s , -50d 36m 58.5s) | C | 180 | 18.3 | 3016 | 2021-08-07 23:44:09 | MASTER-OAFA | (09h 32m 25.02s , -50d 38m 21.0s) | C | 180 | 18.3 | 3196 | 2021-08-07 23:44:09 | MASTER-OAFA | (09h 32m 25.02s , -50d 38m 21.0s) | C | 540 | 18.5 | Coadd 3215 | 2021-08-07 23:47:29 | MASTER-OAFA | (09h 32m 28.03s , -50d 36m 52.9s) | C | 180 | 18.2 | 3415 | 2021-08-07 23:50:49 | MASTER-OAFA | (09h 32m 21.71s , -50d 37m 32.1s) | C | 180 | 18.2 | 3614 | 2021-08-07 23:54:08 | MASTER-OAFA | (09h 32m 21.47s , -50d 36m 31.4s) | C | 180 | 18.1 | 3794 | 2021-08-07 23:54:08 | MASTER-OAFA | (09h 32m 21.47s , -50d 36m 31.5s) | C | 540 | 18.5 | Coadd 3814 | 2021-08-07 23:57:27 | MASTER-OAFA | (09h 32m 27.57s , -50d 37m 32.7s) | C | 180 | 17.9 | 4013 | 2021-08-08 00:00:47 | MASTER-OAFA | (09h 32m 20.35s , -50d 38m 40.0s) | C | 180 | 18.1 | 4212 | 2021-08-08 00:04:06 | MASTER-OAFA | (09h 32m 27.14s , -50d 38m 22.6s) | C | 180 | 18.1 | 4392 | 2021-08-08 00:04:06 | MASTER-OAFA | (09h 32m 27.14s , -50d 38m 22.6s) | C | 540 | 18.5 | Coadd 4412 | 2021-08-08 00:07:26 | MASTER-OAFA | (09h 32m 23.81s , -50d 36m 49.8s) | C | 180 | 18.1 | 4612 | 2021-08-08 00:10:46 | MASTER-OAFA | (09h 32m 23.52s , -50d 38m 37.4s) | C | 180 | 18.1 | 4811 | 2021-08-08 00:14:05 | MASTER-OAFA | (09h 32m 25.80s , -50d 36m 50.7s) | C | 180 | 18.1 | 5330 | 2021-08-08 00:22:44 | MASTER-OAFA | (09h 32m 23.46s , -50d 36m 07.4s) | C | 180 | 17.6 | 5847 | 2021-08-08 00:31:20 | MASTER-OAFA | (09h 32m 22.91s , -50d 38m 05.8s) | C | 180 | 17.5 | 6366 | 2021-08-08 00:40:00 | MASTER-OAFA | (09h 32m 21.93s , -50d 36m 57.0s) | C | 180 | 17.2 | 6884 | 2021-08-08 00:48:38 | MASTER-OAFA | (09h 32m 25.05s , -50d 36m 50.2s) | C | 180 | 17.2 | 7402 | 2021-08-08 00:57:16 | MASTER-OAFA | (09h 32m 16.96s , -50d 36m 40.0s) | C | 180 | 16.9 | 7921 | 2021-08-08 01:05:55 | MASTER-OAFA | (09h 32m 16.80s , -50d 38m 40.1s) | C | 180 | 16.7 | 8437 | 2021-08-08 01:14:31 | MASTER-OAFA | (09h 32m 17.73s , -50d 36m 54.2s) | C | 180 | 16.6 | 8956 | 2021-08-08 01:23:10 | MASTER-OAFA | (09h 32m 20.07s , -50d 36m 39.2s) | C | 180 | 16.1 | 9475 | 2021-08-08 01:31:49 | MASTER-OAFA | (09h 32m 10.94s , -50d 36m 17.5s) | C | 180 | 14.0 | 15602 | 2021-08-08 03:13:56 | MASTER-SAAO | (09h 34m 22.59s , -51d 21m 56.9s) | C | 180 | 17.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30613 SUBJECT: Swift GRB210807.74: Global MASTER-Net observations report DATE: 21/08/08 03:44:56 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, D. Cheryasov (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, 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 GRB210807.74 (trigger No 1064361,05h 34m 52.18s , +22d 12m 36.4s, R=0.05) errorbox 34900 sec after notice time and 34992 sec after trigger time at 2021-08-08 03:33:49 UT, with upper limit up to 17.3 mag. The observations began at zenith distance = 79 deg. The sun altitude is -33.5 deg. The galactic latitude b = -5 deg., longitude l = 185 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1683613 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 35083 | MASTER-IAC | C | 180 | 17.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30615 SUBJECT: GRB 210807C: Enhanced Swift-XRT position DATE: 21/08/08 07:13:18 GMT FROM: Phil Evans at U of Leicester M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team. Using 722 s of XRT Photon Counting mode data and 1 UVOT images for GRB 210807C, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 143.53386, -51.40105 which is equivalent to: RA (J2000): 09h 34m 8.13s Dec (J2000): -51d 24' 03.8" with an uncertainty of 2.0 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30616 SUBJECT: GRB 210807A: correction to the GCN Circ. #30614 Assy optical observations DATE: 21/08/08 10:25:45 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI), N. Pankov (HSE, IKI), S. Belkin (IKI) report on behalf of GRB IKI FuN: The name of GRB was indicated incorrectly in GCN Circ. #30614. The observation and photometry in GCN Circ. #30614 indeed refer to the GRB 210807A. We apologize for possible inconvenience. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30617 SUBJECT: GRB 210807A: Swift-XRT refined Analysis DATE: 21/08/08 12:24:18 GMT FROM: Phil Evans at U of Leicester A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) , M. Capalbi (INAF-IASFPA), D.N. Burrows (PSU), J. D. Gropp (PSU), J.A. Kennea (PSU) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 3.1 ks of XRT data for GRB 210807A (Lien et al. GCN Circ. 30600), from 208 s to 86.2 ks after the BAT trigger. The data comprise 488 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 30603). The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=0.71 (+/-0.09). At T+384 s the decay steepens to an alpha of 2.8 (+0.7, -0.6). The light curve breaks again at T+497 s to a decay with alpha=1.02 (+/-0.03), before a final break at T+32.3 ks s after which the decay index is 2.1 (+1.0, -0.7). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.82 (+/-0.03). The best-fitting absorption column is 5.52 (+0.24, -0.23) x 10^21 cm^-2, in excess of the Galactic value of 3.4 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.71 (+0.15, -0.12) and a best-fitting absorption column consistent with the Galactic value. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.6 x 10^-11 (5.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.4 (+0.6, -0.0) x 10^21 cm^-2 Galactic foreground: 3.4 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 1.71 (+0.15, -0.12) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01064221. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30618 SUBJECT: GRB 210807A: Swift/UVOT Detection DATE: 21/08/08 21:07:25 GMT FROM: Sam LaPorte at PSU GRB 210807A: Swift/UVOT Detection S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210807A 210 s after the BAT trigger (Lien et al., GCN Circ. 30600). A source consistent with the XRT position (Lien et al. GCN Circ. 30600) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 05:06:43.89 = 76.68289 (deg.) Dec (J2000) = +58:14:59.2 = 58.24979 (deg.) with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag b 489 683 38 >17.84 u 639 659 19 >17.04 v 390 583 39 16.58+-0.25 uvw1 440 633 38 >17.12 uvw2 539 721 26 >17.08 white 234 383 147 16.93+-0.04 white 234 708 184 17.19+-0.05 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.409 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30619 SUBJECT: GRB 210807C: Swift/UVOT Upper Limits DATE: 21/08/08 21:44:40 GMT FROM: Sam LaPorte at PSU GRB 210807C: Swift/UVOT Upper Limits S. J. LaPorte (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 210807C 180 s after the BAT trigger (Lien et al., GCN Circ. 30610). No optical afterglow consistent with the XRT position (Lien et al. GCN Circ. 30610) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag v 180 852 596 >19.4 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 3.076 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30620 SUBJECT: GRB 210807C: Fermi GBM detection DATE: 21/08/08 22:58:37 GMT FROM: Suraj Poolakkil at UAH S. Poolakkil (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 22:55:24.31 UT on 7 July 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210807C (trigger 650069729 / 210807955) which was also detected by the Swift/BAT (Lien et al. 2021, GCN 30610). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 61 degrees. The GBM light curve consists of multiple peaks followed by some extended emission with a duration (T90) of about 125 s (50-300 keV). The time-averaged spectrum from T0 s to T0+94.2 s is best fit by a Band function, with Epeak = 170 +/- 28 keV, alpha = -1.08 +/- 0.06 and beta = -1.61 +/- 0.01. The event fluence (10-1000 keV) in this time interval is (56.43 +/- 0.54)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+8.64 s in the 10-1000 keV band is 7.2 +/- 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/" //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30621 SUBJECT: GRB 210807C: Swift-XRT refined Analysis DATE: 21/08/09 06:57:14 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) and A. Y. Lien (GSFC/UMBC) reports on behalf of the Swift-XRT team: We have analysed 5.8 ks of XRT data for GRB 210807C (Lien et al. GCN Circ. 30610), from 183 s to 56.8 ks after the BAT trigger. The data comprise 203 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Goad et al. (GCN Circ. 30615). The light curve can be modelled with a power-law decay with a decay index of alpha=3.11 (+2.96, -0.22), followed by a break at T0+420.7 (+18.1, -165.2) s to a decay of 1.32 (+0.09, -0.07). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.28 (+0.15, -0.14). The best-fitting absorption column is 4.9 (+/-0.4) x 10^22 cm^-2, in excess of the Galactic value of 8.5 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 2.5 (+/-0.6) and a best-fitting absorption column of 6.0 (+1.8, -1.5) x 10^22 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 7.6 x 10^-11 (4.1 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 6.0 (+1.8, -1.5) x 10^22 cm^-2 Galactic foreground: 8.5 x 10^21 cm^-2 Excess significance: 5.5 sigma Photon index: 2.5 (+/-0.6) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01064421. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30623 SUBJECT: GRB 210807A: Swift-BAT refined analysis DATE: 21/08/10 01:41:52 GMT FROM: Sibasish Laha at GSFC T. N. Ukwatta (LANL), 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-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210807A (trigger #1064221) (Lien et al., GCN Circ. 30600). The BAT ground-calculated position is RA, Dec = 76.666, 58.257 deg which is RA(J2000) = 05h 06m 39.7s Dec(J2000) = +58d 15' 25.6" with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment). The partial coding was 28%. The BAT light curve showed a complex structure with a duration of about ~200 sec. T90 (15-350 keV) is 156.30 +- 214.60 sec (estimated error including systematics). The time-averaged spectrum from -19.544 to 640.052 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.26 +- 0.08. The fluence in the 15-150 keV band is 9.5 +- 0.4 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+70.52 sec in the 15-150 keV band is 1.8 +- 0.4 ph/cm2/sec. 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/1064221/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30624 SUBJECT: GRB 210807A: Detection by GRBAlpha DATE: 21/08/10 14:37:22 GMT FROM: Masanori Ohno at Hiroshima University J. Ripa (Masaryk U.), M. Ohno (Eotvos U./Hiroshima U.), H. Takahashi (Hiroshima U.), A. Pal, L. Meszaros, B. Csak (Konkoly Observatory), N. Werner, M. Topinka, F. Munz, 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.), Yuusuke Uchida, Helen Poon, H. Matake, N. Uchida (Hiroshima U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose (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.) -- the GRBAlpha collaboration. The long duration GRB 210807A (Swift-BAT detection; Lien et al. GCN Circ. 30600) was detected by the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020). This is the first time that a GRB was observed by a 1U CubeSat dedicated to gamma-ray burst observations. The data acquisition started at 10:05:14 UT and the tail part of the prompt emission, which consists of multiple peaks, was observed with a duration of about 80 sec. The 7.3 sigma detection significance was confirmed at around 10:06:00 UT. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB210807A.pdf GRBAlpha is a demonstration mission for a future CubeSats constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. GRBAlpha was launched on 2021 March 22 from Baikonur. After its commissioning phase, the scientific observations are now under way. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. 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: 30625 SUBJECT: GRB 210807C: Swift-BAT refined analysis DATE: 21/08/10 21:58:19 GMT FROM: Sibasish Laha at GSFC 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), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 210807C (trigger #1064421) (Lien et al., GCN Circ. 30610). The BAT ground-calculated position is RA, Dec = 143.540, -51.409 deg which is RA(J2000) = 09h 34m 09.7s Dec(J2000) = -51d 24' 32.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 20%. The BAT light curve showed a complex structure with a duration of about ~100 sec. T90 (15-350 keV) is 89.97 +- 6.26 sec (estimated error including systematics). The time-averaged spectrum from T-31.36 to T+78.57 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.65 +- 0.06. The fluence in the 15-150 keV band is 1.2 +- 0.0 x 10^-05 erg/cm2. The 1-sec peak photon flux measured from T-24.22 sec in the 15-150 keV band is 4.0 +- 0.7 ph/cm2/sec. 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/1064421/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30628 SUBJECT: GRB 210807A: Tautenburg observations DATE: 21/08/11 11:37:11 GMT FROM: Ana Nicuesa at TLS Tautenburg S. Schmidl, A. Nicuesa Guelbenzu, S. Klose, S. Melnikov, B. Stecklum, U. Laux (all Tautenburg) and J. Greiner (MPE Garching) report: We observed the field of GRB 210807A (Lien et al., GCN 30600) with the Tautenburg 1.34m Schmidt telescope equipped with the TAUKAM 6kx6k CCD camera. Observations started at 23:19 UT on August 7, about 13 hours after the GRB trigger. For the optical afterglow (Lien et al., GCN 30600; Hu et al., GCN 30602; LaPorte et al. GCN 30618) we measure the following magnitudes: r = 21.66 +/- 0.18, at a midtime of August 7, 23:28 UT, i = 21.25 +/- 0.19, at a midtime of August 8, 01:16 UT, z = 20.52 +/- 0.19, at a midtime of August 8, 01:26 UT. Second-epoch observations were performed the following night. The optical transient was not detected anymore: r 22.2, at a midtime of August 8, 23:34 UT, i 22.4, at a midtime of August 9, 00:38 UT, z 21.2, at a midtime of August 9, 01:20 UT. Given magnitudes are calibrated against the Pan-STARRS catalogue. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30637 SUBJECT: GRB 210807A: continued Assy, AbAO and Mondy observations DATE: 21/08/12 19:34:29 GMT FROM: Alexei Pozanenko at IKI, Moscow S. Belkin (IKI), A. Pozanenko (IKI), V. Kim (FAI, Pulkovo Observatory), R. Ya. Inasaridze (AbAO), E. Klunko (ISTP), M. Krugov (FAI), N. Pankov (HSE), D. Datashvili (AbAO), V. R. Ayvazian (AbAO), G. V. Kapanadze (AbAO) report on behalf of IKI GRB FuN: We continued observation of the GRB 210807A (Lien et al., GCN 30600; Ripa et al., GCN 30624) with AZT-20 of Assy observatory, AZT-33IK of Mondy observatory, and AS-32 of Abastumani observatory. The optical transient GRB 210807A (Lien et al., GCN 30600; Hu et al., GCN 30602; Lipunov et al., GCN 30607; Kim et al., GCNs 30614, 30616; LaPorte et al., GCN 30618; Schmidl et al., GCN 30628) was detected in almost all of our stacked images. Preliminary photometric results are presented below: Date UT start t-T0 Filter Exp. OT Err. UL(3sig) Observ. (mid, days) (s) 2021-08-07 23:46:09 0.58957 R 53*60 20.94 0.09 21.6 AbAO 2021-08-09 17:11:54 2.31822 R 30*120 22.6 0.35 22.5 Mondy 2021-08-10 17:22:17 3.32334 R 27*120 n/d n/d 22.7 Mondy 2021-08-10 21:33:07 3.50135 r(AB) 65*60 23.14 0.26 23.7 Assy The photometry is based on the nearby stars of the USNO-B1.0 catalog. USNO-B1.0_id R2 1482-0188929 16.72 1482-0188954 15.47 1482-0189006 15.38 and based on the same stars presented in PS1 catalog for r(AB) calibrations. The light curve plotted based on available data for can be found at http://grb.rssi.ru/GRB210807A/GRB210807A_LC.png The light curve can be approximated by broken power law with power law indices of -0.55 and -1.05 before and after break at about 0.22 days.