GRB 250703A
GCN Circular 40909
Subject
GRB 250703A: Fermi GBM Final Real-time Localization
Date
2025-07-03T09:28:11Z (a day 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 09:07:31 UT on 3 Jul 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250703A (trigger 773226456.426922 / 250703380).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 337.6, Dec = 26.1 (J2000 degrees, equivalent to J2000 22h 30m, 26d 06'), with a statistical uncertainty of 1.2 degrees.
The angle from the Fermi LAT boresight is 131.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_skymap_all_bn250703380.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/bn250703380/quicklook/glg_healpix_all_bn250703380.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250703380/quicklook/glg_lc_medres34_bn250703380.gif
GCN Circular 40915
Subject
GRB 250703A: DDOTI Optical Upper Limit
Date
2025-07-03T14:00:42Z (17 hours ago)
From
sahil.atri@students.uniroma2.eu
Via
Web form
Sahil Atri (U Roma), Rosa L. Becerra (U Roma), Alan M. Watson (UNAM), Camila Angulo Valdez (UNAM), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), Margarita Pereyra (UNAM) and Eleonora Troja (U Roma) report:
We observed the field of GRB 250703A detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 40909) with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) on the night of 2025-07-03 UTC.
DDOTI observed the Fermi/GBM error region, covering about 92% of the statistical error region (Fermi GBM Team, GCN Circ. 40909). DDOTI observed the field of GRB 250703A from 09:19 UTC to 11:22 UTC (from T+ 0.2 h to T+ 2.2 h after the trigger) and obtained a total exposure of 56 minutes, alternating with other scientific programs.
Comparing our observations to the USNO-B1 and Pan-STARRS PS1 DR2 catalogues, we
detect no uncatalogued fading sources within the observed field down to a 10-sigma limiting AB magnitude of:
w > 20.8
This value is not corrected for the Galactic extinction.
GCN Circular 40930
Subject
Fermi GRB 250703A: Global MASTER-Net observations report
Date
2025-07-04T03:30:23Z (4 hours ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
Via
email
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-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) started inspect of the Fermi GRB 250703A ( Fermi GBM team, GCN 40909) errorbox 54105 sec after notice time and 54115 sec after trigger time at 2025-07-04 00:09:27 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 65 deg. The sun altitude is -68.8 deg.
The galactic latitude b = -27 deg., longitude l = 88 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2924032
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 26m 03.93s , +25d 31m 00.0s) | C | 60 | 18.5 |
54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 24m 08.95s , +25d 46m 54.4s) | C | 60 | 18.4 |
54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 34m 58.48s , +25d 30m 12.9s) | C | 60 | 19.1 |
54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 33m 03.49s , +25d 46m 08.2s) | C | 60 | 19.0 |
54650 | 2025-07-04 00:17:51 | MASTER-SAAO | (22h 22m 02.32s , +23d 35m 41.4s) | C | 60 | 19.0 |
54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 30m 48.83s , +23d 37m 23.1s) | C | 60 | 18.4 |
54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 28m 54.92s , +23d 53m 18.7s) | C | 60 | 18.4 |
54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 26m 00.65s , +25d 30m 36.9s) | C | 60 | 17.6 |
54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 24m 05.05s , +25d 46m 32.8s) | C | 60 | 17.5 |
55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 34m 59.98s , +25d 30m 21.6s) | C | 60 | 18.7 |
55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 33m 04.25s , +25d 46m 18.0s) | C | 60 | 18.6 |
55530 | 2025-07-04 00:32:31 | MASTER-SAAO | (22h 22m 03.38s , +23d 35m 59.0s) | C | 60 | 16.4 |
55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 30m 50.57s , +23d 37m 31.6s) | C | 60 | 18.2 |
55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 28m 55.96s , +23d 53m 28.4s) | C | 60 | 18.1 |
55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 26m 03.12s , +25d 30m 45.9s) | C | 60 | 16.1 |
55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 24m 06.74s , +25d 46m 43.2s) | C | 60 | 16.1 |
58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 34m 57.08s , +25d 32m 08.2s) | C | 60 | 17.9 |
58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 33m 00.18s , +25d 47m 59.5s) | C | 60 | 17.7 |
59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 22m 20.57s , +23d 37m 14.0s) | C | 60 | 18.6 |
59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 20m 26.03s , +23d 53m 02.5s) | C | 60 | 18.4 |
60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 31m 09.34s , +23d 37m 00.4s) | C | 60 | 17.5 |
60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 29m 14.85s , +23d 52m 49.9s) | C | 60 | 17.3 |
60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 26m 26.43s , +25d 32m 54.5s) | C | 60 | 16.6 |
60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 24m 30.30s , +25d 48m 45.4s) | C | 60 | 16.3 |
60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 35m 20.05s , +25d 32m 35.8s) | C | 60 | 15.5 |
60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 33m 23.77s , +25d 48m 27.9s) | C | 60 | 15.3 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.