GCN Circular 40927
Subject
GRB 250702F: Fermi GBM Observation
Event
Date
2025-07-04T00:25:21Z (14 hours ago)
From
oindabimukherjee@gmail.com
Via
Web form
O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:
"At 21:06:43.10 UT on 02 July 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250702F (trigger 773183208/250702880).
which was also detected by Swift BAT (N. J. Klingler et al. 2025), GOTO (A. Kumar et al. 2025, GCN 40896), AKO (Mohammad Odeh et al. 2025, GCN 40925).
A spectroscopic redshift of z = 1.52 was reported by GTC/OSIRIS (A. de Ugarte Postigo et al. 2025, GCN 40901)
The Fermi GBM on-ground location is consistent with the Swift BAT position.
The angle from the Fermi LAT boresight is 43 degrees.
The GBM light curve consists of multiple pulses with a duration (T90)
of about 54 s (50-300 keV). The time-averaged spectrum
from T0-29 to T0+48 s is best fit by
a band function with alpha = -1.34 +/- 0.06 and beta = -1.78 +/- 0.09 and the cutoff energy,
parameterized as Epeak, is 403 +/- 148 keV.
The event fluence (10-1000 keV) in this time interval is
(1.45 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+38 s in the 10-1000 keV band is 9.7 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html
For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"