GRB 250307A
GCN Circular 39618
Subject
GRB 250307A: Fermi GBM Final Real-time Localization
Date
2025-03-07T20:08:14Z (3 months ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 19:57:53 UT on 7 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250307A (trigger 763070278.733804 / 250307832).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 265.6, Dec = 2.2 (J2000 degrees, equivalent to J2000 17h 42m, 2d 12'), with a statistical uncertainty of 2.7 degrees.
The angle from the Fermi LAT boresight is 82.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250307832/quicklook/glg_skymap_all_bn250307832.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250307832/quicklook/glg_healpix_all_bn250307832.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250307832/quicklook/glg_lc_medres34_bn250307832.gif
GCN Circular 39620
Subject
Fermi GRB 250307A: Global MASTER-Net observations report
Date
2025-03-08T00:30:39Z (3 months ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko,
A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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 (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 250307A ( Fermi GBM team, GCN 39618) errorbox 12559 sec after notice time and 12601 sec after trigger time at 2025-03-07 23:27:54 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 70 deg. The sun altitude is -42.9 deg.
The galactic latitude b = 16 deg., longitude l = 27 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2803750
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
12631 | 2025-03-07 23:27:54 | MASTER-Kislovodsk | (17h 39m 34.52s , +03d 16m 16.2s) | C | 60 | 16.0 |
13390 | 2025-03-07 23:40:34 | MASTER-Kislovodsk | (17h 47m 30.44s , +03d 15m 20.9s) | C | 60 | 16.9 |
13470 | 2025-03-07 23:41:53 | MASTER-Kislovodsk | (17h 39m 36.28s , +03d 16m 01.7s) | C | 60 | 17.1 |
13550 | 2025-03-07 23:43:13 | MASTER-Kislovodsk | (17h 38m 11.65s , +01d 21m 58.9s) | C | 60 | 16.9 |
15377 | 2025-03-08 00:13:10 | MASTER-Kislovodsk | (17h 40m 28.55s , +02d 25m 26.0s) | C | 120 | 17.0 |
15517 | 2025-03-08 00:15:30 | MASTER-Kislovodsk | (17h 40m 32.95s , +02d 24m 17.6s) | C | 120 | 17.7 |
15656 | 2025-03-08 00:17:49 | MASTER-Kislovodsk | (17h 40m 27.31s , +00d 23m 17.3s) | C | 120 | 17.9 |
15796 | 2025-03-08 00:20:09 | MASTER-Kislovodsk | (17h 40m 31.50s , +00d 23m 28.7s) | C | 120 | 17.9 |
16015 | 2025-03-08 00:24:18 | MASTER-Kislovodsk | (17h 40m 31.73s , +02d 23m 54.6s) | C | 60 | 17.1 |
16095 | 2025-03-08 00:25:39 | MASTER-Kislovodsk | (17h 46m 12.95s , +01d 24m 43.6s) | C | 60 | 17.4 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.