[vsnet-grb-info 27996] GRB 210528A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30099
SUBJECT: GRB 210528A: Fermi GBM detection
DATE:    21/05/29 15:34:40 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 14:03:46.16 UT on 28 May 2021, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 210528A (trigger 643903431 /
210528586).

The on-ground calculated location, using the GBM trigger data, is
reported in GCN #30090.

The GBM light curve consists of a strong pulse with some overlapping
structure and a duration (T90) of about 1 s (50-300 keV). The
time-averaged spectrum from T0-0.3 s to T0+1.3 s is
best fit by a power law function with an exponential high-energy
cutoff.  The power law index is -0.47 +/- 0.06 and the cutoff energy,
parameterized as Epeak, is 210 +/- 9 keV.

The event fluence (10-1000 keV) in this time interval is (3.90 +/-
0.12)E-6 erg/cm^2. The 64ms peak photon flux measured starting from T0
+ 0.256 s in the 10-1000 keV band is 31.7 +/- 2.0 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/"