[vsnet-grb-info 12625] GRB 121123A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13985
SUBJECT: GRB 121123A: Fermi GBM observation
DATE:    12/11/23 19:16:43 GMT
FROM:    Suzanne Foley at MPE  <sfoley at mpe.mpg.de>

S. Foley (UCD)
reports on behalf of the Fermi GBM Team:

"At 10:06:00.59 UT on 23 November 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located the second emission episode of GRB 121123A
(trigger 375357963 / 121123421) which was also detected by the
Swift/BAT (Helder et al. 2012, GCN 13982,
http://gcn.gsfc.nasa.gov/notices_s/sw00539358000msbx.gif).
The emission detected by GBM is contemporaneous with the UVOT
observation of an afterglow candidate for GRB 121123A reported by
Helder et al.
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight is 85 degrees.

The GBM light curve consists of a single peak with a long tail
with a duration (T90) of about 102 s (50-300 keV).
The time-averaged spectrum from T0+3.1 s to T0+106.5 s is
well fit by a Band function with Epeak = 85 (+/-3) keV,
alpha = -0.25 (+/-0.09), and beta = -3.0 (+0.2/-0.3).

The event fluence (10-1000 keV) in this time interval is
(2.20 +/- 0.08)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+32.6 s in the 10-1000 keV band
is 4.00 +/- 0.25 ph/s/cm^2.


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