GRB 250309A
GCN Circular 39623
Subject
GRB 250309A: Fermi GBM Final Real-time Localization
Date
2025-03-09T00:53:02Z (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 SHORT GRB
At 00:42:03 UT on 9 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250309A (trigger 763173728.785018 / 250309029).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 46.7, Dec = 58.0 (J2000 degrees, equivalent to J2000 03h 06m, 58d 00'), with a statistical uncertainty of 22.9 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/bn250309029/quicklook/glg_skymap_all_bn250309029.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/bn250309029/quicklook/glg_healpix_all_bn250309029.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250309029/quicklook/glg_lc_medres34_bn250309029.gif
GCN Circular 39640
Subject
Fermi GRB 250309A: Global MASTER-Net observations report
Date
2025-03-09T22:31:05Z (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 250309A ( Fermi GBM team, GCN 39623) errorbox 71845 sec after notice time and 71879 sec after trigger time at 2025-03-09 20:40:03 UT, with upper limit up to 16.2 mag. The observations began at zenith distance = 81 deg. The sun altitude is -50.2 deg.
The galactic latitude b = 0 deg., longitude l = 140 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2805313
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
71900 | 2025-03-09 20:40:03 | MASTER-Kislovodsk | (02h 47m 28.83s , +38d 43m 03.4s) | C | 40 | 15.5 |
71955 | 2025-03-09 20:40:03 | MASTER-Kislovodsk | (02h 47m 28.84s , +38d 43m 03.3s) | C | 150 | 16.2 | Coadd
71965 | 2025-03-09 20:41:03 | MASTER-Kislovodsk | (02h 47m 28.70s , +38d 42m 52.8s) | C | 50 | 15.4 |
72040 | 2025-03-09 20:42:13 | MASTER-Kislovodsk | (02h 47m 28.63s , +38d 42m 43.8s) | C | 60 | 15.6 |
72130 | 2025-03-09 20:43:33 | MASTER-Kislovodsk | (02h 47m 28.55s , +38d 42m 35.0s) | C | 80 | 15.7 |
72240 | 2025-03-09 20:43:33 | MASTER-Kislovodsk | (02h 47m 28.54s , +38d 42m 34.9s) | C | 300 | 16.1 | Coadd
72240 | 2025-03-09 20:45:13 | MASTER-Kislovodsk | (02h 47m 28.42s , +38d 42m 25.5s) | C | 100 | 15.8 |
72370 | 2025-03-09 20:47:13 | MASTER-Kislovodsk | (02h 47m 28.29s , +38d 42m 16.6s) | C | 120 | 15.7 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.