[vsnet-grb-info 21854] GRB 190311A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23953
SUBJECT: GRB 190311A: Fermi GBM observation
DATE:    19/03/12 02:09:13 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 14:23:37.601 UT on 11 March 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190311A (trigger 574007022 / 190311600),
which was also detected by the Swift/BAT
(Troja et al., GCN 23946). The GBM on-ground location is consistent with
the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 128
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 12.5 s (50-300 keV).
The time-averaged spectrum from T0-4.1 s to T0+3.1 s is
adequately fit by a simple power law function with index 1.86 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(1.40 +/- 0.18)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-2.75 s in the 10-1000 keV band
is 3.00 +/- 0.35 ph/s/cm^2.

A power law function with an exponential
high-energy cutoff fits the spectrum equally well
with Epeak= 89 +/- 34 keV and alpha = -1.51 +/- 0.25.


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