[vsnet-grb-info 17885] GRB 160422A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19331
SUBJECT: GRB 160422A: Fermi GBM observation
DATE:    16/04/22 21:44:08 GMT
FROM:    Eric Burns at U of Alabama  <eb0016 at uah.edu>

E. Burns (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 11:59:00.81 UT on 22 April 2016, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 160422A (trigger 483019144 / 160422499).

The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux of the GRB.
This ARR was accepted and the spacecraft slewed to the GBM in-flight
location. The initial angle from the Fermi LAT boresight to
the LAT location is 53 degrees. The GBM on-ground location is
consistent with the LAT location (Yassine et al., GCN 19329).

The GBM light curve consists of a single main peak
with a duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0 s to T0+13.1 s is
well fit by a Band function with Epeak = 242 +/- 4 keV,
alpha = -0.95 +/- 0.01, and beta = -2.42 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is
(8.68 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+8.0 s in the 10-1000 keV band
is 93.8 +/- 0.6 ph/s/cm^2.

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