[vsnet-grb-info 28454] GRB 210730A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30557
SUBJECT: GRB 210730A: Fermi GBM observation
DATE:    21/07/30 21:05:04 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood at nasa.gov>

J. Wood (NASA/MSFC)
reports on behalf of the Fermi GBM Team:

"At 04:57:29.03 UT on 30 July 2021, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 210730A (trigger 649313854 / 210730207)
which was also detected by the Swift/BAT and Swift/XRT (E. Sonbas et al. 2021, GCN 30548).

The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 32 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 5 s (50-300 keV).
The time-averaged spectrum from T0 to T0+6 s is
well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.68 +/- 0.07 and
the cutoff energy, parameterized as Epeak, is 170 +/- 11 keV

The event fluence (10-1000 keV) in this time interval is
(2.9 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.3 s in the 10-1000 keV band
is 10.5 +/- 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/"