[vsnet-grb-info 28492] GRB 210803A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30595
SUBJECT: GRB 210803A: Fermi GBM observation
DATE:    21/08/04 09:07:17 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi at ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 11:55:44.40 UT on 3 August 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210803A (trigger 649684549 / 210803497).
The on-ground calculated location, using the GBM trigger data, is

RA = 218.7, DEC = -21.4

(J2000 degrees, equivalent to 14h 34m, -21d 24'),
with a statistical uncertainty of 1 degree (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight
at the GBM trigger time is 98 degrees.

The GBM light curve consists of bright, FRED-like emission episode
with a duration (T90) of about 9 s (50-300 keV).
The time-averaged spectrum from T0 to T0+9 s is
well fit by a Band function with Epeak = 164 +/- 19 keV,
alpha = -1.20 +/- 0.05, and beta = -2.06 +/- 0.07.

The event fluence (10-1000 keV) in this time interval is
(1.28 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.4 s in the 10-1000 keV band
is 35.7 +/- 0.6 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/"