Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 30519

GRB 210725A: Fermi GBM detection
2021-07-26T16:48:00Z (3 years ago)
Suraj Poolakkil at UAH <>
S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 03:47:03.54 UT on 25 July 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210725A (trigger 648877628 / 210725158)
which was also detected by the Swift/BAT (Bernardini et al. 2021, GCN
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 78

The GBM light curve consists of a single peak followed by some
extended emission with a duration (T90) of about 47 s (50-300 keV).
The time-averaged spectrum from T0-1.02 s to T0+9.21 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.37 +/- 0.22  and
the cutoff energy, parameterized as Epeak, is 460 +/- 104 keV.

The event fluence (10-1000 keV) in this time interval is
(3.14 +/- 0.35)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.64 s in the 10-1000 keV band
is 2.0 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:

For Fermi GBM data and info, please visit the official Fermi GBM Support
Looking for U.S. government information and services? Visit