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[vsnet-grb-info 41233] IceCube Alert 251218.85: Global MASTER-Net observations report
by GCN Circulars 18 Dec '25

18 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43150 SUBJECT: IceCube Alert 251218.85: Global MASTER-Net observations report DATE: 25/12/18 20:39:21 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the IceCube Alert 251218.85 (trigger No 9008919,23h 34m 08.64s , +44d 08m 42.0s, R=0.51) errorbox 64 sec after notice time and 107 sec after trigger time at 2025-12-18 20:22:48 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 57 deg. The sun altitude is -68.4 deg. MASTER-Tunka robotic telescope located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the IceCube Alert 251218.85 errorbox 247 sec after notice time and 290 sec after trigger time at 2025-12-18 20:25:51 UT, with upper limit up to 18.0 mag. The observations began at zenith distance = 80 deg. The sun altitude is -42.5 deg. The galactic latitude b = -16 deg., longitude l = 109 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3076097 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 117 | 2025-12-18 20:22:48 | MASTER-Kislovodsk | (23h 32m 34.10s , +44d 07m 24.4s) | P- | 20 | 16.8 | 117 | 2025-12-18 20:22:48 | MASTER-Kislovodsk | (23h 32m 25.71s , +44d 29m 51.7s) | P| | 20 | 16.9 | 162 | 2025-12-18 20:23:28 | MASTER-Kislovodsk | (23h 32m 33.96s , +44d 07m 21.9s) | P- | 30 | 17.0 | 321 | 2025-12-18 20:25:51 | MASTER-Tunka | (23h 34m 38.20s , +44d 21m 36.4s) | C | 60 | 18.0 | 321 | 2025-12-18 20:25:51 | MASTER-Tunka | (23h 34m 16.79s , +44d 26m 39.9s) | C | 60 | 17.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43150. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41232] GRB 251214B: VIRT Optical Upper Limit
by GCN Circulars 18 Dec '25

18 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43149 SUBJECT: GRB 251214B: VIRT Optical Upper Limit DATE: 25/12/18 16:23:01 GMT FROM: Priya Gokuldass at ERAU <gokuldap(a)my.erau.edu> P. Gokuldass (ERAU), F. George (UVI), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), and T. Lombardi (Eckerd College) report: We observed the field of long GRB 251214B detected by Fermi (Fermi team, GCN 43088), Swift (Eyles-Ferris et al., GCN 43089; Kuin and Eyles-Ferris, GCN 43105; Burrows et al., GCN 43112), and GECAM-B (Luo et al., GCN 43113) with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2025-12-14 starting at 23:12:24.856 UTC (T-mid ~ T0 + ~15h). We performed a series of exposures in an R filter with a total exposure of 1210s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 2.06. We do not detect any source at the enhanced XRT position reported (Evans et al., GCN 43098). This non-detection is consistent with reported detections (Eyles-Ferris et al., GCN 43089; Kang et al., GCN 43093; Gress et al., GCN 43095; Fu et al., GCN 43097; Gupta et al., GCN 43100; Watson et al., GCN 43103; Kuin and Eyles-Ferris, GCN 43105; Pérez-Fournon et al., GCN 43123, de Ugarte Postigo et al., GCN 43131) and upper limits (Volnova et al., GCN 43124; Pankov et al., GCN 43132; Volnova et al., GCN 43141; Lin et al., GCN 43134). We report the following 3-sigma upper limit: T_mid ||Exposure ||Filter ||Limit T+ ~15h || 1210s || R || > 20.4 The limit is estimated from comparison to nearby Gaia D3 synphot stars and is not corrected for Galactic extinction. We acknowledge the use of STDWeb interface to verify our result. We acknowledge financial support in part from NASA EPSCoR 80NNSC22M0063, NSF AST 2319415, and NASA EPSCoR 80NSSC24M0112. This message can be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/43149. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41231] Fermi trigger No 787736968: Global MASTER-Net observations report
by GCN Circulars 18 Dec '25

18 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43148 SUBJECT: Fermi trigger No 787736968: Global MASTER-Net observations report DATE: 25/12/18 12:30:39 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB251218.33 (trigger No 787736968,01h 20m 19.20s , +08d 31m 12.0s, R=2) errorbox 12771 sec after notice time and 12805 sec after trigger time at 2025-12-18 11:22:48 UT, with upper limit up to 15.0 mag. The observations began at zenith distance = 44 deg. The sun altitude is -21.0 deg. The galactic latitude b = -53 deg., longitude l = 136 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3075501 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 12835 | 2025-12-18 11:22:48 | MASTER-Tunka | (01h 32m 31.99s , +10d 56m 59.4s) | C | 60 | 15.0 | 12835 | 2025-12-18 11:22:48 | MASTER-Tunka | (01h 32m 06.93s , +11d 03m 54.2s) | C | 60 | 14.7 | 13495 | 2025-12-18 11:33:47 | MASTER-Tunka | (01h 16m 38.29s , +09d 03m 21.8s) | C | 60 | 14.6 | 13495 | 2025-12-18 11:33:47 | MASTER-Tunka | (01h 16m 13.08s , +09d 10m 03.4s) | C | 60 | 14.5 | 15014 | 2025-12-18 11:59:06 | MASTER-Tunka | (01h 31m 58.57s , +09d 01m 47.3s) | C | 60 | 13.3 | 15014 | 2025-12-18 11:59:06 | MASTER-Tunka | (01h 31m 32.75s , +09d 08m 12.9s) | C | 60 | 13.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43148. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41230] Fermi GRB 251217A: Global MASTER-Net observations report
by GCN Circulars 17 Dec '25

17 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43147 SUBJECT: Fermi GRB 251217A: Global MASTER-Net observations report DATE: 25/12/17 10:30:42 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 251217A ( Fermi GBM team, GCN 43146) errorbox 20114 sec after notice time and 20149 sec after trigger time at 2025-12-17 10:11:24 UT, with upper limit up to 15.0 mag. Observations started at twilight. The observations began at zenith distance = 34 deg. The sun altitude is -10.4 deg. The galactic latitude b = -24 deg., longitude l = 75 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3074063 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 20179 | 2025-12-17 10:11:24 | MASTER-Tunka | (21h 35m 28.03s , +20d 25m 27.5s) | C | 60 | 13.1 | 20179 | 2025-12-17 10:11:24 | MASTER-Tunka | (21h 34m 58.00s , +20d 33m 14.0s) | C | 60 | 13.2 | Coadd 20292 | 2025-12-17 10:13:16 | MASTER-Tunka | (21h 51m 44.22s , +20d 24m 29.5s) | C | 60 | 13.4 | 20292 | 2025-12-17 10:13:16 | MASTER-Tunka | (21h 51m 14.04s , +20d 32m 16.2s) | C | 60 | 13.3 | Coadd 20380 | 2025-12-17 10:14:44 | MASTER-Tunka | (21h 35m 47.63s , +22d 17m 22.2s) | C | 60 | 14.0 | 20380 | 2025-12-17 10:14:44 | MASTER-Tunka | (21h 35m 16.43s , +22d 25m 10.6s) | C | 60 | 13.9 | Coadd 20471 | 2025-12-17 10:16:15 | MASTER-Tunka | (21h 52m 15.88s , +22d 17m 38.4s) | C | 60 | 14.4 | 20471 | 2025-12-17 10:16:15 | MASTER-Tunka | (21h 51m 44.47s , +22d 25m 28.7s) | C | 60 | 14.1 | Coadd 20551 | 2025-12-17 10:17:35 | MASTER-Tunka | (21h 36m 35.83s , +18d 30m 47.9s) | C | 60 | 14.1 | 20551 | 2025-12-17 10:17:35 | MASTER-Tunka | (21h 36m 06.57s , +18d 38m 25.9s) | C | 60 | 14.0 | Coadd 20627 | 2025-12-17 10:18:52 | MASTER-Tunka | (21h 37m 36.82s , +24d 11m 25.5s) | C | 60 | 14.7 | 20627 | 2025-12-17 10:18:52 | MASTER-Tunka | (21h 37m 04.28s , +24d 19m 15.4s) | C | 60 | 14.7 | Coadd 20696 | 2025-12-17 10:20:01 | MASTER-Tunka | (21h 52m 37.33s , +18d 31m 07.7s) | C | 60 | 14.3 | 20697 | 2025-12-17 10:20:01 | MASTER-Tunka | (21h 52m 07.99s , +18d 38m 46.5s) | C | 60 | 14.4 | Coadd 20780 | 2025-12-17 10:21:25 | MASTER-Tunka | (21h 54m 10.78s , +24d 12m 19.4s) | C | 60 | 15.0 | 20780 | 2025-12-17 10:21:25 | MASTER-Tunka | (21h 53m 38.02s , +24d 20m 11.0s) | C | 60 | 14.8 | Coadd 20859 | 2025-12-17 10:22:43 | MASTER-Tunka | (21h 39m 01.33s , +16d 37m 07.5s) | C | 60 | 14.1 | 20859 | 2025-12-17 10:22:43 | MASTER-Tunka | (21h 38m 33.01s , +16d 44m 37.9s) | C | 60 | 14.1 | Coadd 20904 | 2025-12-17 10:23:29 | MASTER-Tunka | (21h 40m 56.75s , +26d 06m 13.6s) | C | 60 | 14.7 | 20904 | 2025-12-17 10:23:29 | MASTER-Tunka | (21h 40m 22.72s , +26d 14m 06.3s) | C | 60 | 14.8 | 20978 | 2025-12-17 10:24:42 | MASTER-Tunka | (21h 54m 49.93s , +16d 35m 09.2s) | C | 60 | 13.9 | 20978 | 2025-12-17 10:24:42 | MASTER-Tunka | (21h 54m 21.45s , +16d 42m 40.1s) | C | 60 | 13.9 | 21053 | 2025-12-17 10:25:57 | MASTER-Tunka | (21h 18m 53.52s , +20d 30m 39.4s) | C | 60 | 14.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43147. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41229] Fermi GRB 251217A: Global MASTER-Net observations report
by GCN Circulars 17 Dec '25

17 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43147 SUBJECT: Fermi GRB 251217A: Global MASTER-Net observations report DATE: 25/12/17 10:30:42 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 251217A ( Fermi GBM team, GCN 43146) errorbox 20114 sec after notice time and 20149 sec after trigger time at 2025-12-17 10:11:24 UT, with upper limit up to 15.0 mag. Observations started at twilight. The observations began at zenith distance = 34 deg. The sun altitude is -10.4 deg. The galactic latitude b = -24 deg., longitude l = 75 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3074063 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 20179 | 2025-12-17 10:11:24 | MASTER-Tunka | (21h 35m 28.03s , +20d 25m 27.5s) | C | 60 | 13.1 | 20179 | 2025-12-17 10:11:24 | MASTER-Tunka | (21h 34m 58.00s , +20d 33m 14.0s) | C | 60 | 13.2 | Coadd 20292 | 2025-12-17 10:13:16 | MASTER-Tunka | (21h 51m 44.22s , +20d 24m 29.5s) | C | 60 | 13.4 | 20292 | 2025-12-17 10:13:16 | MASTER-Tunka | (21h 51m 14.04s , +20d 32m 16.2s) | C | 60 | 13.3 | Coadd 20380 | 2025-12-17 10:14:44 | MASTER-Tunka | (21h 35m 47.63s , +22d 17m 22.2s) | C | 60 | 14.0 | 20380 | 2025-12-17 10:14:44 | MASTER-Tunka | (21h 35m 16.43s , +22d 25m 10.6s) | C | 60 | 13.9 | Coadd 20471 | 2025-12-17 10:16:15 | MASTER-Tunka | (21h 52m 15.88s , +22d 17m 38.4s) | C | 60 | 14.4 | 20471 | 2025-12-17 10:16:15 | MASTER-Tunka | (21h 51m 44.47s , +22d 25m 28.7s) | C | 60 | 14.1 | Coadd 20551 | 2025-12-17 10:17:35 | MASTER-Tunka | (21h 36m 35.83s , +18d 30m 47.9s) | C | 60 | 14.1 | 20551 | 2025-12-17 10:17:35 | MASTER-Tunka | (21h 36m 06.57s , +18d 38m 25.9s) | C | 60 | 14.0 | Coadd 20627 | 2025-12-17 10:18:52 | MASTER-Tunka | (21h 37m 36.82s , +24d 11m 25.5s) | C | 60 | 14.7 | 20627 | 2025-12-17 10:18:52 | MASTER-Tunka | (21h 37m 04.28s , +24d 19m 15.4s) | C | 60 | 14.7 | Coadd 20696 | 2025-12-17 10:20:01 | MASTER-Tunka | (21h 52m 37.33s , +18d 31m 07.7s) | C | 60 | 14.3 | 20697 | 2025-12-17 10:20:01 | MASTER-Tunka | (21h 52m 07.99s , +18d 38m 46.5s) | C | 60 | 14.4 | Coadd 20780 | 2025-12-17 10:21:25 | MASTER-Tunka | (21h 54m 10.78s , +24d 12m 19.4s) | C | 60 | 15.0 | 20780 | 2025-12-17 10:21:25 | MASTER-Tunka | (21h 53m 38.02s , +24d 20m 11.0s) | C | 60 | 14.8 | Coadd 20859 | 2025-12-17 10:22:43 | MASTER-Tunka | (21h 39m 01.33s , +16d 37m 07.5s) | C | 60 | 14.1 | 20859 | 2025-12-17 10:22:43 | MASTER-Tunka | (21h 38m 33.01s , +16d 44m 37.9s) | C | 60 | 14.1 | Coadd 20904 | 2025-12-17 10:23:29 | MASTER-Tunka | (21h 40m 56.75s , +26d 06m 13.6s) | C | 60 | 14.7 | 20904 | 2025-12-17 10:23:29 | MASTER-Tunka | (21h 40m 22.72s , +26d 14m 06.3s) | C | 60 | 14.8 | 20978 | 2025-12-17 10:24:42 | MASTER-Tunka | (21h 54m 49.93s , +16d 35m 09.2s) | C | 60 | 13.9 | 20978 | 2025-12-17 10:24:42 | MASTER-Tunka | (21h 54m 21.45s , +16d 42m 40.1s) | C | 60 | 13.9 | 21053 | 2025-12-17 10:25:57 | MASTER-Tunka | (21h 18m 53.52s , +20d 30m 39.4s) | C | 60 | 14.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43147. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41228] GRB 251217A: Fermi GBM Final Real-time Localization
by GCN Circulars 17 Dec '25

17 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43146 SUBJECT: GRB 251217A: Fermi GBM Final Real-time Localization DATE: 25/12/17 04:46:13 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 04:35:34 UT on 17 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251217A (trigger 787638939.89203 / 251217191). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 325.8, Dec = 20.9 (J2000 degrees, equivalent to J2000 21h 43m, 20d 53'), with a statistical uncertainty of 6.6 degrees. The angle from the Fermi LAT boresight is 29.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251217191/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251217191/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251217191/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43146. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41227] GRB 251215A: Swift/UVOT Upper LImits
by GCN Circulars 16 Dec '25

16 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43145 SUBJECT: GRB 251215A: Swift/UVOT Upper LImits DATE: 25/12/16 18:52:06 GMT FROM: S. R. Oates at Lancaster University <samantha.oates(a)ucl.ac.uk> S. R. Oates (Lancaster U.) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251215A 32 ks after the Fermi/GBM trigger (Fermi GBM team, GCN Circ. 43104). No optical afterglow is found in the initial UVOT exposures. The UVOT exposures include the positions of XRT sources 2, 5, 6 and 8 (Osborne et al., GCN 43137). The positions of XRT sources 2, 6, and 8 are consistent with known USNO-B1 sources. No optical source is found consistent with XRT source 5. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag/3sigUL white 31995 49531 4297 >22.4 The magnitudes in the table are not corrected for the Galactic extinction due to the significant reddening of E(B-V) = 0.87 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/43145. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41226] GRB 251215A: Fermi GBM Observation
by GCN Circulars 16 Dec '25

16 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43144 SUBJECT: GRB 251215A: Fermi GBM Observation DATE: 25/12/16 18:31:35 GMT FROM: Peter Veres at University of Alabama in Huntsville <veresp(a)gmail.com> P. Veres (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 04:21:21.57 UT on 15 December 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251215A (trigger 787465286/251215181), which was also detected by Swift-BAT-GUANO (Ronchini et al. 2025, GCN 43114), Swift-XRT (Osborne et al. 2025, GCN 43137) and Glowbug (Cheung et al. 2025, GCN 43133). The real-time Fermi GBM location (GCN 43104) is consistent with the Swift-BAT position. The GBM light curve consists of multiple overlapping pulses with a duration (T90) of about 143 s (50-300 keV). The time-averaged spectrum from T0-37 to T0+162 s is best fit by a Band function with Epeak = 35 +/- 7 keV, alpha = -1 +/- 0.3, and beta = -1.97 +/- 0.03. The event fluence (10-1000 keV) in this time interval is (2.05 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+64 s in the 10-1000 keV band is 5.7 +/- 0.2 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/" View this GCN Circular online at https://gcn.nasa.gov/circulars/43144. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41225] Fermi GRB 251216A: Global MASTER-Net observations report
by GCN Circulars 16 Dec '25

16 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43143 SUBJECT: Fermi GRB 251216A: Global MASTER-Net observations report DATE: 25/12/16 15:15:46 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 251216A ( Fermi GBM team, GCN 43139) errorbox 17500 sec after notice time and 17536 sec after trigger time at 2025-12-16 14:30:26 UT, with upper limit up to 16.4 mag. Observations started at twilight. The observations began at zenith distance = 39 deg. The sun altitude is -9.5 deg. The galactic latitude b = 16 deg., longitude l = 84 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3072907 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 10659 | 2025-12-16 12:35:18 | MASTER- | (18h 38m 20.71s , +53d 19m 42.3s) | C | 60 | 16.9 | 10659 | 2025-12-16 12:35:18 | MASTER- | (18h 34m 27.90s , +54d 21m 36.1s) | C | 60 | 18.4 | 10732 | 2025-12-16 12:36:31 | MASTER- | (19h 08m 51.53s , +57d 04m 35.2s) | C | 60 | 16.8 | 10732 | 2025-12-16 12:36:31 | MASTER- | (19h 04m 35.12s , +58d 06m 38.4s) | C | 60 | 18.6 | 10803 | 2025-12-16 12:37:43 | MASTER- | (18h 39m 15.37s , +51d 24m 37.8s) | C | 60 | 16.9 | 10804 | 2025-12-16 12:37:43 | MASTER- | (18h 35m 33.19s , +52d 26m 36.2s) | C | 60 | 18.3 | 10876 | 2025-12-16 12:38:55 | MASTER- | (18h 38m 26.95s , +55d 13m 43.2s) | C | 60 | 17.2 | 10876 | 2025-12-16 12:38:55 | MASTER- | (18h 34m 24.25s , +56d 15m 38.2s) | C | 60 | 18.5 | 10948 | 2025-12-16 12:40:07 | MASTER- | (18h 40m 06.35s , +57d 07m 35.6s) | C | 60 | 17.5 | 10948 | 2025-12-16 12:40:07 | MASTER- | (18h 35m 51.37s , +58d 09m 31.1s) | C | 60 | 18.8 | 11020 | 2025-12-16 12:41:19 | MASTER- | (18h 17m 27.03s , +49d 32m 48.1s) | C | 60 | 17.3 | 11020 | 2025-12-16 12:41:19 | MASTER- | (18h 13m 54.31s , +50d 34m 39.8s) | C | 60 | 18.7 | 11090 | 2025-12-16 12:42:29 | MASTER- | (18h 21m 25.26s , +47d 38m 46.3s) | C | 60 | 17.0 | 11090 | 2025-12-16 12:42:29 | MASTER- | (18h 18m 00.39s , +48d 40m 42.0s) | C | 60 | 18.5 | 11162 | 2025-12-16 12:43:41 | MASTER- | (19h 05m 47.90s , +55d 11m 36.3s) | C | 60 | 16.7 | 11162 | 2025-12-16 12:43:41 | MASTER- | (19h 01m 45.00s , +56d 13m 43.0s) | C | 60 | 18.4 | 11236 | 2025-12-16 12:44:55 | MASTER- | (18h 14m 21.88s , +51d 27m 57.8s) | C | 60 | 17.6 | 11236 | 2025-12-16 12:44:56 | MASTER- | (18h 10m 40.69s , +52d 29m 48.2s) | C | 60 | 19.0 | 11308 | 2025-12-16 12:46:07 | MASTER- | (18h 12m 17.10s , +53d 21m 26.9s) | C | 60 | 18.0 | 11379 | 2025-12-16 12:47:18 | MASTER- | (18h 11m 09.66s , +55d 15m 24.9s) | C | 60 | 18.0 | 11592 | 2025-12-16 12:50:51 | MASTER- | (18h 37m 50.00s , +50d 33m 22.3s) | C | 60 | 18.4 | 11592 | 2025-12-16 12:50:51 | MASTER- | (18h 41m 22.81s , +49d 31m 20.8s) | C | 60 | 16.8 | 11662 | 2025-12-16 12:52:02 | MASTER- | (18h 23m 00.92s , +46d 46m 30.2s) | C | 60 | 18.5 | 11662 | 2025-12-16 12:52:02 | MASTER- | (18h 26m 18.41s , +45d 44m 32.4s) | C | 60 | 17.1 | 11734 | 2025-12-16 12:53:13 | MASTER- | (19h 00m 27.50s , +54d 20m 11.0s) | C | 60 | 18.2 | 11734 | 2025-12-16 12:53:13 | MASTER- | (19h 04m 18.96s , +53d 18m 04.3s) | C | 60 | 16.7 | 12313 | 2025-12-16 13:02:52 | MASTER- | (19h 00m 30.09s , +52d 26m 38.2s) | C | 60 | 18.0 | 12313 | 2025-12-16 13:02:52 | MASTER- | (19h 04m 12.17s , +51d 24m 33.7s) | C | 60 | 16.8 | 12386 | 2025-12-16 13:04:05 | MASTER- | (18h 41m 05.95s , +48d 40m 19.4s) | C | 60 | 18.2 | 12386 | 2025-12-16 13:04:05 | MASTER- | (18h 44m 31.00s , +47d 38m 20.4s) | C | 60 | 16.8 | 12462 | 2025-12-16 13:05:21 | MASTER- | (19h 33m 25.72s , +58d 05m 27.0s) | C | 60 | 18.6 | 12462 | 2025-12-16 13:05:21 | MASTER- | (19h 37m 41.47s , +57d 03m 16.7s) | C | 60 | 16.9 | 13173 | 2025-12-16 13:17:12 | MASTER- | (19h 01m 48.72s , +50d 33m 15.2s) | C | 60 | 17.1 | 13173 | 2025-12-16 13:17:12 | MASTER- | (19h 03m 38.43s , +49d 31m 52.6s) | C | 60 | 16.2 | 13244 | 2025-12-16 13:18:23 | MASTER- | (19h 26m 40.81s , +54d 18m 19.9s) | C | 60 | 16.9 | 13244 | 2025-12-16 13:18:23 | MASTER- | (19h 28m 40.23s , +53d 16m 50.2s) | C | 60 | 15.8 | 13448 | 2025-12-16 13:21:47 | MASTER- | (18h 45m 14.40s , +46d 46m 00.1s) | C | 60 | 16.7 | 13448 | 2025-12-16 13:21:47 | MASTER- | (18h 46m 55.96s , +45d 44m 41.8s) | C | 60 | 16.1 | 13660 | 2025-12-16 13:25:19 | MASTER- | (19h 05m 51.95s , +47d 37m 13.2s) | C | 60 | 15.7 | 13660 | 2025-12-16 13:25:19 | MASTER- | (19h 04m 06.22s , +48d 38m 39.8s) | C | 60 | 16.3 | 13876 | 2025-12-16 13:28:55 | MASTER- | (20h 12m 11.03s , +58d 56m 54.9s) | C | 60 | 15.8 | 17567 | 2025-12-16 14:30:26 | MASTER-Kislovodsk | (19h 11m 54.53s , +50d 38m 45.8s) | C | 60 | 12.7 | 17567 | 2025-12-16 14:30:26 | MASTER-Kislovodsk | (19h 05m 06.15s , +50d 59m 03.9s) | C | 60 | 15.6 | 17646 | 2025-12-16 14:31:46 | MASTER-Kislovodsk | (19h 12m 58.52s , +54d 27m 44.3s) | C | 60 | 12.5 | 17646 | 2025-12-16 14:31:46 | MASTER-Kislovodsk | (19h 05m 29.24s , +54d 48m 25.8s) | C | 60 | 15.5 | 17726 | 2025-12-16 14:33:05 | MASTER-Kislovodsk | (19h 41m 23.34s , +52d 34m 21.3s) | C | 60 | 13.1 | 17726 | 2025-12-16 14:33:05 | MASTER-Kislovodsk | (19h 34m 12.59s , +52d 54m 40.2s) | C | 60 | 15.1 | 17806 | 2025-12-16 14:34:25 | MASTER-Kislovodsk | (19h 33m 39.17s , +54d 28m 28.9s) | C | 60 | 12.6 | 17806 | 2025-12-16 14:34:25 | MASTER-Kislovodsk | (19h 26m 10.96s , +54d 49m 21.1s) | C | 60 | 15.7 | 17892 | 2025-12-16 14:35:51 | MASTER-Kislovodsk | (19h 01m 46.32s , +52d 33m 50.3s) | C | 60 | 12.7 | 17892 | 2025-12-16 14:35:51 | MASTER-Kislovodsk | (18h 54m 42.14s , +52d 54m 07.7s) | C | 60 | 15.5 | 17992 | 2025-12-16 14:37:32 | MASTER-Kislovodsk | (19h 40m 34.70s , +48d 46m 44.1s) | C | 60 | 13.3 | 17992 | 2025-12-16 14:37:32 | MASTER-Kislovodsk | (19h 34m 00.53s , +49d 07m 08.5s) | C | 60 | 15.9 | 18072 | 2025-12-16 14:38:52 | MASTER-Kislovodsk | (19h 04m 00.90s , +48d 43m 49.3s) | C | 60 | 13.6 | 18072 | 2025-12-16 14:38:52 | MASTER-Kislovodsk | (18h 57m 32.23s , +49d 04m 10.6s) | C | 60 | 16.2 | 18152 | 2025-12-16 14:40:12 | MASTER-Kislovodsk | (19h 26m 23.52s , +56d 22m 48.8s) | C | 60 | 13.3 | 18152 | 2025-12-16 14:40:12 | MASTER-Kislovodsk | (19h 18m 33.48s , +56d 42m 51.8s) | C | 60 | 16.1 | 18235 | 2025-12-16 14:41:34 | MASTER-Kislovodsk | (19h 49m 49.49s , +50d 41m 24.3s) | C | 60 | 13.6 | 18235 | 2025-12-16 14:41:34 | MASTER-Kislovodsk | (19h 42m 55.13s , +51d 02m 14.9s) | C | 60 | 16.0 | 18315 | 2025-12-16 14:42:54 | MASTER-Kislovodsk | (18h 52m 48.80s , +50d 38m 56.0s) | C | 60 | 13.8 | 18315 | 2025-12-16 14:42:54 | MASTER-Kislovodsk | (18h 46m 05.95s , +50d 59m 17.0s) | C | 60 | 16.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/43143. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41224] GRB 251202A/EP251202a: Koshka optical upper limit
by GCN Circulars 16 Dec '25

16 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43142 SUBJECT: GRB 251202A/EP251202a: Koshka optical upper limit DATE: 25/12/16 14:47:43 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> A. A. Volnova (IKI), A. Novichonok (Petrozavodsk State University, KIAM), A. S. Pozanenko (IKI), N. S. Pankov (HSE, IKI) report on behalf of IKI-GRB-FuN: We observed the field of GRB 251202A/EP251202a (Fermi GBM team, GCN 42933; Zhang et al., GCN 42937; Sbarufatti et al., GCN 42943; Liang et al., GCN 42946; Bala, GCN 42957; Arya et al., GCN 42967; Guo et al., GCN 42970, GCN 42997) with the Zeiss-1000 telescope of the Simeiz (Koshka) observatory (INASAN) taking several 90-second expositions in R-band starting on Dec.05 UT 21:38:48. In the stacked image we do not detect the optical counterpart reported previously (Zhu et al., GCN 42939; O’Neill et al., GCN 42947; Quirola-Vasquez et al., GCN 42948; Kuin and Moss, GCN 42956; Zheng et al., GCN 42964; Ma et al., GCN 42966; Bochenek et al., GCN 42977; Contreras et al., GCN 42999; Giarratana et al., GCN 43128). Preliminary photometry and observational details are the following: Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope (mid,days) (n*s) (3sigma) 2025-12-05 21:38:48 3.86988 68*90 R n/d n/d 19.7 Simeiz/Zeiss-1000 The photometry is based on several nearby stars from the USNO-B1 catalogue (R2 magnitudes) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43142. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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