[vsnet-grb-info 7674] GRB 090422: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9228
SUBJECT: GRB 090422: Fermi GBM observation
DATE:    09/04/24 15:57:39 GMT
FROM:    Sheila McBreen at MPE  <smcbreen at mpe.mpg.de>

Sheila McBreen (UCD/MPE)
reports on behalf of the Fermi GBM Team:

"At 03:35:17.07 UT on 22 April 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090422 (trigger 262064119 / 090422150)
which was also detected by the Swift-BAT (Ukwatta et al. 2009, GCN 9185
& Markwardt et al. 2009, GCN 9195). The GBM on-ground location is
consistent with the Swift position.
The angle from the Fermi LAT boresight is 29 degrees.

The GBM light curve consists of 2 pulses
with a duration (T90) of about 10 s (8-1000 keV).
The time-averaged spectrum from T0-2.4 s to T0+10.8 s is
adequately fit by a simple power law function with
index 1.81 +/- 0.15 (chi squared 358 for 361 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.0 +/- 0.1)E-6 erg/cm^2. The 0.128 sec peak photon flux measured
starting from T0-0.256 s in the 8-1000 keV band
is 7.8 +/- 0.5 ph/s/cm^2.