June 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 38901] GRB 250628A: Swift-XRT refined Analysis
by GCN Circulars 28 Jun '25

28 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40857 SUBJECT: GRB 250628A: Swift-XRT refined Analysis DATE: 25/06/28 10:41:22 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), M.A. Williams (PSU) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 8.2 ks of XRT data for GRB 250628A, from 127 s to 27.6 ks after the trigger. The data comprise 47 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The light curve can be modelled with a series of power-law decays. The initial decay index is alpha=5.0 (+0.6, -0.5). At T+358 s the decay flattens to an alpha of -0.01 (+0.11, -0.13) before breaking again at T+14.4 ks to a final decay with index alpha=2.6 (+/-0.6). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.92 (+0.17, -0.16). The best-fitting absorption column is 3.2 (+0.8, -0.7) x 10^21 cm^-2, in excess of the Galactic value of 2.3 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 4.0 x 10^-11 (5.8 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 3.2 (+0.8, -0.7) x 10^21 cm^-2 Galactic foreground: 2.3 x 10^20 cm^-2 Excess significance: 6.8 sigma Photon index: 1.92 (+0.17, -0.16) If the light curve continues to decay with a power-law decay index of 2.6, the count rate at T+24 hours will be 1.6 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.5 x 10^-14 (9.3 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01328546. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/40857. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38900] Fermi GRB 250626A: Global MASTER-Net observations report
by GCN Circulars 28 Jun '25

28 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40856 SUBJECT: Fermi GRB 250626A: Global MASTER-Net observations report DATE: 25/06/28 09:15:21 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) 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 250626A ( Fermi GBM team, GCN 40845) errorbox 42909 sec after notice time and 42944 sec after trigger time at 2025-06-27 10:09:38 UT, with upper limit up to 20.6 mag. The observations began at zenith distance = 33 deg. The sun altitude is -17.4 deg. The galactic latitude b = -60 deg., longitude l = 174 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2917440 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 42975 | 2025-06-27 10:09:38 | MASTER-OAFA | (01h 27m 40.95s , -06d 22m 32.0s) | C | 60 | 20.0 | 43050 | 2025-06-27 10:10:53 | MASTER-OAFA | (01h 35m 38.27s , -06d 23m 08.1s) | C | 60 | 20.0 | 43110 | 2025-06-27 10:10:53 | MASTER-OAFA | (01h 35m 38.27s , -06d 23m 08.1s) | C | 180 | 20.6 | Coadd 43127 | 2025-06-27 10:12:11 | MASTER-OAFA | (01h 43m 25.19s , -08d 17m 09.9s) | C | 60 | 20.0 | 43187 | 2025-06-27 10:12:11 | MASTER-OAFA | (01h 43m 25.19s , -08d 17m 09.9s) | C | 180 | 20.5 | Coadd 43202 | 2025-06-27 10:13:26 | MASTER-OAFA | (01h 51m 23.61s , -08d 18m 09.1s) | C | 60 | 20.0 | 43262 | 2025-06-27 10:13:26 | MASTER-OAFA | (01h 51m 23.61s , -08d 18m 09.0s) | C | 180 | 20.6 | Coadd 43279 | 2025-06-27 10:14:43 | MASTER-OAFA | (01h 27m 42.13s , -06d 23m 32.1s) | C | 60 | 20.0 | 43356 | 2025-06-27 10:16:00 | MASTER-OAFA | (01h 35m 41.34s , -06d 22m 03.8s) | C | 60 | 20.0 | 43432 | 2025-06-27 10:17:15 | MASTER-OAFA | (01h 43m 21.97s , -08d 17m 48.3s) | C | 60 | 19.9 | 43507 | 2025-06-27 10:18:31 | MASTER-OAFA | (01h 51m 30.29s , -08d 16m 20.6s) | C | 60 | 19.9 | 43584 | 2025-06-27 10:19:48 | MASTER-OAFA | (01h 27m 36.11s , -06d 22m 51.4s) | C | 60 | 19.9 | 43662 | 2025-06-27 10:21:06 | MASTER-OAFA | (01h 35m 38.40s , -06d 21m 53.5s) | C | 60 | 19.9 | 43740 | 2025-06-27 10:22:24 | MASTER-OAFA | (01h 43m 24.60s , -08d 16m 55.6s) | C | 60 | 19.9 | 43817 | 2025-06-27 10:23:40 | MASTER-OAFA | (01h 51m 25.10s , -08d 17m 56.0s) | C | 60 | 19.9 | 43895 | 2025-06-27 10:24:58 | MASTER-OAFA | (01h 27m 42.16s , -06d 23m 26.4s) | C | 60 | 19.9 | 43955 | 2025-06-27 10:24:58 | MASTER-OAFA | (01h 27m 42.16s , -06d 23m 26.4s) | C | 180 | 20.4 | Coadd 43976 | 2025-06-27 10:26:20 | MASTER-OAFA | (01h 35m 41.71s , -06d 22m 14.2s) | C | 60 | 19.7 | 44036 | 2025-06-27 10:26:20 | MASTER-OAFA | (01h 35m 41.71s , -06d 22m 14.2s) | C | 180 | 20.3 | Coadd 44052 | 2025-06-27 10:27:35 | MASTER-OAFA | (01h 43m 22.34s , -08d 17m 41.1s) | C | 60 | 19.7 | 44128 | 2025-06-27 10:28:51 | MASTER-OAFA | (01h 51m 30.01s , -08d 16m 15.3s) | C | 60 | 19.9 | 44188 | 2025-06-27 10:28:51 | MASTER-OAFA | (01h 51m 30.01s , -08d 16m 15.3s) | C | 180 | 20.1 | Coadd 44205 | 2025-06-27 10:30:08 | MASTER-OAFA | (01h 27m 36.78s , -06d 22m 37.6s) | C | 60 | 19.6 | 44280 | 2025-06-27 10:31:23 | MASTER-OAFA | (01h 35m 38.45s , -06d 21m 40.2s) | C | 60 | 19.7 | 44357 | 2025-06-27 10:32:40 | MASTER-OAFA | (01h 43m 24.82s , -08d 16m 42.8s) | C | 60 | 19.6 | 44432 | 2025-06-27 10:33:55 | MASTER-OAFA | (01h 51m 24.68s , -08d 17m 43.2s) | C | 60 | 19.4 | 44509 | 2025-06-27 10:35:12 | MASTER-OAFA | (01h 27m 41.68s , -06d 23m 28.0s) | C | 60 | 19.3 | 44586 | 2025-06-27 10:36:29 | MASTER-OAFA | (01h 35m 42.04s , -06d 21m 57.7s) | C | 60 | 19.1 | 44661 | 2025-06-27 10:37:44 | MASTER-OAFA | (01h 43m 22.75s , -08d 17m 23.0s) | C | 60 | 19.2 | 44737 | 2025-06-27 10:39:00 | MASTER-OAFA | (01h 51m 30.94s , -08d 15m 47.5s) | C | 60 | 19.0 | 44813 | 2025-06-27 10:40:16 | MASTER-OAFA | (01h 27m 36.58s , -06d 22m 24.0s) | C | 60 | 18.7 | 44891 | 2025-06-27 10:41:35 | MASTER-OAFA | (01h 35m 38.99s , -06d 21m 26.8s) | C | 60 | 18.7 | 44967 | 2025-06-27 10:42:50 | MASTER-OAFA | (01h 43m 25.32s , -08d 16m 28.8s) | C | 60 | 18.5 | 45041 | 2025-06-27 10:44:05 | MASTER-OAFA | (01h 51m 24.79s , -08d 17m 30.2s) | C | 60 | 18.5 | 45119 | 2025-06-27 10:45:22 | MASTER-OAFA | (01h 27m 41.21s , -06d 23m 11.7s) | C | 60 | 18.2 | 45195 | 2025-06-27 10:46:39 | MASTER-OAFA | (01h 35m 42.25s , -06d 21m 27.0s) | C | 60 | 18.1 | 45270 | 2025-06-27 10:47:54 | MASTER-OAFA | (01h 43m 23.07s , -08d 17m 00.6s) | C | 60 | 16.4 | 123302 | 2025-06-28 08:28:25 | MASTER-OAFA | (01h 34m 53.55s , -07d 07m 29.7s) | C | 60 | 19.8 | 123376 | 2025-06-28 08:29:39 | MASTER-OAFA | (01h 34m 53.39s , -07d 06m 26.5s) | C | 60 | 19.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/40856. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38899] Swift GRB 250628A: Global MASTER-Net observations report
by GCN Circulars 28 Jun '25

28 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40855 SUBJECT: Swift GRB 250628A: Global MASTER-Net observations report DATE: 25/06/28 05:58:35 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) 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 GRB 250628A ( M. Ferro et al., GCN 40853) errorbox 17683 sec after notice time and 17722 sec after trigger time at 2025-06-28 05:51:18 UT, with upper limit up to 16.0 mag. The observations began at zenith distance = 81 deg. The sun altitude is -72.0 deg. The galactic latitude b = -66 deg., longitude l = 246 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2918453 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 17812 | MASTER-OAFA | C | 180 | 16.0 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/40855. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38898] GRB 250628A: Enhanced Swift-XRT position
by GCN Circulars 28 Jun '25

28 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40854 SUBJECT: GRB 250628A: Enhanced Swift-XRT position DATE: 25/06/28 04:48:11 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 1647 s of XRT Photon Counting mode data and 4 UVOT images for GRB 250628A, 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 = 38.55311, -38.07894 which is equivalent to: RA (J2000): 02h 34m 12.75s Dec (J2000): -38d 04' 44.2" with an uncertainty of 2.4 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. View this GCN Circular online at https://gcn.nasa.gov/circulars/40854. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38897] GRB 250628A: Swift detection of a burst
by GCN Circulars 28 Jun '25

28 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40853 SUBJECT: GRB 250628A: Swift detection of a burst DATE: 25/06/28 01:13:26 GMT FROM: James DeLaunay at PSU <jjd330(a)psu.edu> M. Ferro (INAF-OAB), R. Brivio (INAF-OAB), J. J. DeLaunay (PSU), R. Gupta (NASA GSFC) and D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift Observatory Team: At 00:55:56.71 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 250628A (trigger=1328546). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 38.551, -38.081 which is RA(J2000) = 02h 34m 12s Dec(J2000) = -38d 04' 50" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed two emission pulses with the first brighter pulse starting from T0-20 sec to T0+20 sec and the second fainter pulse from T0+25 end T0+60 sec. The peak count rate was ~1066 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 00:57:57.7 UT, 121.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, uncatalogued X-ray source with an enhanced position: RA, Dec 38.55240, -38.07909 which is equivalent to: RA(J2000) = 02h 34m 12.58s Dec(J2000) = -38d 04' 44.7" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 7.9 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 gives a column density in excess of the Galactic value (2.30 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.1 (+4.01/-3.17) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 9.47e-10 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 129 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 19.6 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 mag. No correction has been made for the expected extinction corresponding to E(B-V) of 0.023. Burst Advocate for this burst is M. Ferro (matteo.ferro AT inaf.it). 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/) View this GCN Circular online at https://gcn.nasa.gov/circulars/40853. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38896] GRB 250625A: Swift-BAT refined analysis
by GCN Circulars 27 Jun '25

27 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40852 SUBJECT: GRB 250625A: Swift-BAT refined analysis DATE: 25/06/27 23:16:03 GMT FROM: Amy <yarleen(a)gmail.com> A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), M. Ferro (INAF-OAB), R. Gupta (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GSFC), D. M. Palmer (LANL), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+100 sec from the recent telemetry downlink, we report further analysis of BAT GRB 250625A (trigger #1327910) (Ferro et al., GCN Circ. 40825). The BAT ground-calculated position is RA, Dec = 261.517, 22.245 deg which is RA(J2000) = 17h 26m 04.1s Dec(J2000) = +22d 14' 40.7" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 68%. The mask-weighted light curve shows a single-pulse structure that starts at ~T0, peaks at ~T+2 s, and ends at ~T+6 s. T90 (15-350 keV) is 4.00 +- 1.41 sec (estimated error including systematics). The time-averaged spectrum from T-0.35 to T+3.65 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.00 +- 0.22. The fluence in the 15-150 keV band is 2.8 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.65 sec in the 15-150 keV band is 0.8 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1327910 View this GCN Circular online at https://gcn.nasa.gov/circulars/40852. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38895] GRB 250625A: Leavitt Observatory afterglow detection
by GCN Circulars 27 Jun '25

27 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40851 SUBJECT: GRB 250625A: Leavitt Observatory afterglow detection DATE: 25/06/27 19:20:11 GMT FROM: leavittob(a)gmail.com L. Moretti, E. Pavoni (Leavitt Observatory, Italy) Members of: GRB/UAI - Gamma Ray Burst Section of Unione Astrofili Italiani ATA - Associazione Tuscolana di Astronomia In a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), report: We imaged the field of GRB 250625A, which was detected by Swift-BA (Ferro et al., GCN 40825) and Fermi-GBM (GCN 40824) with our RC telescope (D=250 mm, F/D=8) of Leavitt Observatory. The observations began approximately 4.6 hours after the trigger, with good weather conditions, stacking a series of 12 exposures of 120 seconds each. All images are unfiltered and were processed by a single data processing pipeline based on astropy package (Astropy Collaboration et al., 2022ApJ...935..167A). In the stacked frame, we detected a very faint object at the following position: R.A. (J2000) = 17:26:01.92 Dec. (J2000) = +22:16:04.31 with the following photometry: Date UT at mid-exposure Filter Mag. Err. 2025-06-25 20:58:29 UTC CR 21.4 +/-0.2 CR magnitude is unfiltered with R zero point. Magnitudes were estimated with the Pan-STARRS cat. and are derived using Lupton (2005) equations. Not corrected for galactic dust extinction. This measure is consistent with the optical afterglow reported by Moskvitin et al. (GCN 40828), Xin et al. (GCN 40830), Zhu et al. (GCN 40834), Fortin et al. (GCN 40837), Adami et al. (GCN 40838), Brosio et al. (GCN 40839), Wang et al. (GCN 40841), Ruocco et al. (GCN 40843), de Ugarte Postigo et al. (GCN 40846). The message may be cited. Reference: https://leavittobservatory.altervista.org View this GCN Circular online at https://gcn.nasa.gov/circulars/40851. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38894] Fermi Gamma-ray Burst Monitor trigger 772732642/250627665 is not a GRB
by GCN Circulars 27 Jun '25

27 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40850 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 772732642/250627665 is not a GRB DATE: 25/06/27 17:30:12 GMT FROM: Lorenzo Scotton at UAH <lscottongcn(a)outlook.com> L. Scotton (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 772732642/250627665 at 15:57:17.97 UT on 27 June 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to local particles." View this GCN Circular online at https://gcn.nasa.gov/circulars/40850. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38893] Fermi Gamma-ray Burst Monitor trigger 772720540/250627525 is not a GRB
by GCN Circulars 27 Jun '25

27 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40849 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 772720540/250627525 is not a GRB DATE: 25/06/27 13:51:38 GMT FROM: Marianna Dafčíková at Masaryk University <500025(a)mail.muni.cz> M. Dafcikova (MUNI) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 772720540/250627525 at 12:35:35.78 UT on 27 June 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to SAA entry." View this GCN Circular online at https://gcn.nasa.gov/circulars/40849. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38892] GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations
by GCN Circulars 27 Jun '25

27 Jun '25

TITLE: GCN CIRCULAR NUMBER: 40848 SUBJECT: GRB 250625A: AbAO and INASAN Kislovodsk Optical Observations DATE: 25/06/27 11:55:09 GMT FROM: Nicolai Pankov at HSE, IKI RAS <colinsergesen(a)gmail.com> N. Pankov (HSE, IKI), R. Ya. Inasaridze (AbAO), A. Tarasenkov (INASAN), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 250625A (Fermi GBM Team, GCN 40824; Ferro et al., GCN 40825; Beardmore et al., GCN 40827; Dichiara et al., GCN 40835; Di Lalla et al., GCN 40836) using the 0.7-meter AS-32 telescope of Abastumani Observatory (AbAO) and the 0.5-meter RC-500 telescope of INASAN Kislovodsk Observatory. The observations at AbAO started on 2025-06-25 at 17:41:35 UT and consisted of 71*60 sec exposures. The observations at RC-500 were carried out between 2025-06-25 18:19:40 UT and 2025-06-26 00:09:04 UT using 120 sec exposures. We do not detect the optical afterglow reported/followed by (Moskvitin et al., GCN 40828, Xin et al., GCN 40830; Malesani et al., GCN 40831; Lipunov et al., GCN 40826/40832; Zhu et al., GCN 40834, Fortin et al., GCN 40837; Adami et. al, GCN 40838; Brosio et. al, GCN 40839; Breeveld & Ferro, GCN 40840; WU et. al, GCN 40842; Ruocco et. al, GCN 40843; de Ugarte Postigo et. al, GCN 40846) in the R-band co-add images. The preliminary photometry is as follows: Date UT start t-T0 Exp. Filter OT Err. UL Telescope (mid, days) (n*s) (3sigma) 2025-06-25 17:41:35 0.09176 71*60 R n/d n/d 20.0 AS-32 2025-06-25 18:38:08 0.14735 59*120 R n/d n/d 21.5 RC-500 The photometry has calibrated using stars from USNO-B1.0 (see Moskvitin et al., GCN 40828) and has not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/40848. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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