GRB 250617A
GCN Circular 40758
Subject
GRB 250617A: Fermi GBM Final Real-time Localization
Date
2025-06-17T16:19:51Z (9 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 16:09:13 UT on 17 Jun 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250617A (trigger 771869358.345712 / 250617673).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 354.8, Dec = 35.4 (J2000 degrees, equivalent to J2000 23h 39m, 35d 23'), with a statistical uncertainty of 2.6 degrees.
The angle from the Fermi LAT boresight is 51.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250617673/quicklook/glg_skymap_all_bn250617673.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/bn250617673/quicklook/glg_healpix_all_bn250617673.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250617673/quicklook/glg_lc_medres34_bn250617673.gif
GCN Circular 40781
Subject
Fermi GRB 250617A: Global MASTER-Net observations report
Date
2025-06-18T22:15:43Z (8 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-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 250617A ( Fermi GBM team, GCN 40758) errorbox 1 days 17814 sec after notice time and 1 days 17823 sec after trigger time at 2025-06-18 21:06:16 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 66 deg. The sun altitude is -23.6 deg.
The galactic latitude b = -25 deg., longitude l = 107 deg.
Real time updated cover map and OT discovered available here:
https://master.sai.msu.ru/site/master2/observ.php?id=2905762
We obtain a following upper limits.
Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
104253 | 2025-06-18 21:06:16 | MASTER-Kislovodsk | (23h 40m 51.75s , +35d 31m 02.8s) | C | 60 | 17.7 |
104540 | 2025-06-18 21:11:02 | MASTER-Kislovodsk | (23h 27m 52.38s , +37d 23m 28.9s) | C | 60 | 16.0 |
104624 | 2025-06-18 21:12:26 | MASTER-Kislovodsk | (23h 37m 52.75s , +37d 24m 33.4s) | C | 60 | 16.3 |
104845 | 2025-06-18 21:16:08 | MASTER-Kislovodsk | (23h 46m 54.05s , +37d 24m 18.0s) | C | 60 | 17.3 |
104928 | 2025-06-18 21:17:31 | MASTER-Kislovodsk | (23h 57m 02.84s , +37d 22m 47.1s) | C | 60 | 16.6 |
105010 | 2025-06-18 21:18:53 | MASTER-Kislovodsk | (23h 40m 51.77s , +35d 28m 47.9s) | C | 60 | 17.1 |
Filter C is a clear (unfiltred) band.
The observation and reduction will continue.
The message may be cited.