GRB 250505A
GCN Circular 40348
Subject
GRB 250505A: Fermi GBM Final Real-time Localization
Date
2025-05-05T08:19:09Z (24 days 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 08:08:39 UT on 5 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250505A (trigger 768125324.539978 / 250505339).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 104.6, Dec = -10.3 (J2000 degrees, equivalent to J2000 06h 58m, -10d 18'), with a statistical uncertainty of 3.4 degrees.
The angle from the Fermi LAT boresight is 22.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250505339/quicklook/glg_skymap_all_bn250505339.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/bn250505339/quicklook/glg_healpix_all_bn250505339.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250505339/quicklook/glg_lc_medres34_bn250505339.gif
GCN Circular 40352
Subject
Fermi GRB 250505A: Global MASTER-Net observations report
Date
2025-05-05T17:15:53Z (24 days 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 250505A ( Fermi GBM team, GCN 40348) errorbox 31206 sec after notice time and 31236 sec after trigger time at 2025-05-05 16:49:16 UT, with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenith distance = 37 deg. The sun altitude is -11.5 deg.
The galactic latitude b = -3 deg., longitude l = 223 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2861221
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
31267 | 2025-05-05 16:49:16 | MASTER-SAAO | (06h 52m 27.70s , -10d 20m 11.1s) | C | 60 | 18.0 |
31346 | 2025-05-05 16:50:35 | MASTER-SAAO | (07h 00m 40.59s , -10d 18m 52.3s) | C | 60 | 17.9 |
31426 | 2025-05-05 16:51:55 | MASTER-SAAO | (06h 55m 08.68s , -12d 12m 30.2s) | C | 60 | 18.1 |
31506 | 2025-05-05 16:53:15 | MASTER-SAAO | (07h 03m 25.46s , -12d 13m 27.5s) | C | 60 | 18.0 |
31586 | 2025-05-05 16:54:35 | MASTER-SAAO | (06h 50m 15.46s , -08d 25m 58.2s) | C | 60 | 18.2 |
32311 | 2025-05-05 17:06:40 | MASTER-SAAO | (06h 52m 25.86s , -10d 18m 53.6s) | C | 60 | 18.5 |
32390 | 2025-05-05 17:07:59 | MASTER-SAAO | (07h 00m 29.83s , -10d 19m 51.8s) | C | 60 | 18.3 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.