[vsnet-grb-info 25166] GRB 200228B: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27266
SUBJECT: GRB 200228B: Fermi GBM observation
DATE:    20/02/28 20:54:53 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood at nasa.gov>

E. Bissaldi (Politecnico and INFN Bari), C. Meegan (UAH), and J. Wood (NASA/MSFC)
report on behalf of the Fermi GBM Team:

"At 11:14:43.89 UT on 28 February 2020, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 200228B (trigger 604581288 / 200228469),
which was also detected by the Swift/BAT (Laha et al. 2020, GCN 27254).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 59 degrees.

The GBM light curve shows a single emission episode
with a duration (T90) of about 14 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+11 s is
adequately fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.17 +/- 0.33 and
the cutoff energy, parameterized as Epeak, is 76 +/- 16 keV.

The event fluence (10-1000 keV) in this time interval is
(1.30 +/- 0.18)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.3 s in the 10-1000 keV band
is 1.4 +/- 0.2 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/"