Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 8720

GRB 081223: Fermi GBM detection
2008-12-24T12:33:20Z (15 years ago)
Elisabetta Bissaldi at MPE <>
Elisabetta Bissaldi (MPE)
reports on behalf of the Fermi GBM Team: 

"At 10:03:57.15 UT on 23 December 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081223 (trigger 251719438 / 081223419).
The on-ground calculated location, using the GBM trigger
data, is RA = 116.7, Dec = 33.5 (J2000 degrees,
equivalent to 07h 47m, 33d 30'), with an uncertainty
of 6.2 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 28 degrees.

This short burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of a single spike
with a duration (T90) of about 890 ms (8-1000 keV).
The time-averaged spectrum from T0-0.078 s to T0+0.434 s is
adequately fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.63 +/- 0.10 and
the cutoff energy, parameterized as Epeak, is 280 +/- 30 keV
(chi squared 334 for 318 d.o.f.).

The event fluence (8-1000 keV) in this time interval is 
(1.20 +/- 0.10)E-06 erg/cm^2. The 64-ms peak photon flux
measured starting from T0+0.114 s in the 
8-1000 keV band is 22 +/- 3 ph/s/cm^2.

The spectral analysis results presented above are preliminary; 
final results will be published in the GBM GRB Catalog."
Looking for U.S. government information and services? Visit