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 10355

GRB 100122A: Fermi GBM detection
2010-01-23T02:32:50Z (14 years ago)
Narayana Bhat at U Alabama/Huntsville/GBM <>
A. von Kienlin (MPE), P. N. Bhat (UAH) and R. D. Preece (UAH)
report on behalf of the Fermi GBM Team:

"At 14:47:37.31 UT on 22 January 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100122A (trigger 285864459 / 100122616).

The on-ground calculated location, using the GBM trigger
data, is RA = 79.2 , DEC = -2.7 (J2000 degrees,
equivalent to 05h 16.8m, -2d 42'), with an uncertainty
of 1.3 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 45 degrees.

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

The GBM light curve consists of 2 pulses (a weak pulse at trigger followed
by a much larger pulse about 21 s later) with a duration (T90)
of about 6.6 s (8-1000 keV).
The time-averaged spectrum from T0-2.688 s to T0+25.984 s is
adequately fit by a Band function with Epeak = 45.6 +/- 1.5 keV,
alpha = -0.98 +/- 0.05, and beta = -2.31 +/- 0.03

(CSTAT 1673 for 478 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(1.00 +/- 0.01)E-05 erg/cm^2. The 1.0-sec peak photon flux measured
starting from T0+20.9 s in the 8-1000 keV band
is 10.44 +/- 0.07 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