[vsnet-grb-info 6967] GRB 081120: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8551
SUBJECT: GRB 081120: Fermi GBM detection
DATE:    08/11/25 17:00:02 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs at mpe.mpg.de>

Elisabetta Bissaldi (MPE) reports on behalf of the Fermi GBM Team:


"At 14:49:34.57 UT on 20 November 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081120 (trigger 248885375 / 081120618).
The on-ground calculated location, using the GBM trigger
data, is RA = 205.4, Dec = -9.1 (J2000 degrees,
equivalent to 13h 42m, -09d 06'), with an uncertainty
of 6 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 84 degrees.

The GRB light curve consists of two peaks and has a
duration (T90) of about 12 s (8-1000 keV).
The time-averaged spectrum from T0-3.072 s to T0+6.144 s
is best fit by a Band function with Epeak = 44 +/- 5 keV,
alpha = 0.4 +/- 0.5 and beta = -2.18 +/- 0.10
(chi squared 367 for 353 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.7 +/- 0.9)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.048 s in the 8-1000 keV band
is 5.1 +/- 1.6 ph/s/cm^2.


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