[vsnet-grb-info 10151] GRB 110123A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11600
SUBJECT: GRB 110123A: Fermi GBM detection
DATE:    11/01/25 00:31:13 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst at nasa.gov>

A.J. van der Horst (USRA) and D. Gruber (MPE) report on behalf
of the Fermi GBM Team:

"At 19:17:45.03 UT on 23 January 2011, the Fermi Gamma-Ray Burst
Monitor triggered and located GRB 110123A (trigger 317503067 /
110123804). The on-ground location, using the GBM trigger data, is
RA = 247.0, Dec = +28.0 (J2000 degrees, equivalent to 17h40m, +28d02'),
with an uncertainty of 1.64 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic error which is
currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 58 degrees. This GRB was
bright enough to result in a Fermi spacecraft repointing maneuver.

The GBM light curve consists of one main peak with substructure, with
a duration (T90) of 17.9 +/- 0.8 s (50-300 keV). The time-averaged
spectrum from T0-1.8 s to T0+22.8 s is best fit by a Band function with
Epeak = 280 +/- 15 keV, alpha = -0.64 +/- 0.03, and beta = -1.96 +/- 0.05.
The event fluence (10-1000 keV) in this time interval is
(2.61 +/- 0.03)E-5 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+8.4 s in the 10-1000 keV band is
8.3 +/- 0.2 ph/s/cm^2.

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