Skip to main content
Introducing Einstein Probe, Astro Flavored Markdown, and Notices Schema v4.0.0. See news and announcements

GCN Circular 10225

GRB 091126B: Fermi GBM detection
2009-12-01T16:57:03Z (15 years ago)
Sheila McBreen at MPE <>
S. McBreen (UCD/MPE) reports on behalf
of the Fermi GBM Team:

"At 09:19:48.53 UT on 26 November 2009, the Fermi Gamma-Ray
Burst Monitor triggered and located a short burst GRB 091126B
(trigger 280919990/091126389).
The on-ground calculated location, using the GBM trigger
data, is RA = 47.4, DEC = 31.5 (J2000 degrees,
equivalent to 03 h 10 m, 31 d 30 '), with an uncertainty
of 14.3 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 60 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.

The GBM light curve consists of one pulse
with a duration of about 30 ms (8-1000 keV).
The time-averaged spectrum from T0-0.016 s to T0+0.016 s is
adequately  fit by a power law function with an exponential
high energy cutoff.  The power law index is -0.23 (+0.32/-0.23) and
the cutoff energy, parameterized as Epeak, is 731 (+229/-165) keV
(CSTAT 753 for 846 d.o.f.).

The event fluence (8-1000 keV) in this time interval is
(2.2 +/- 0.02)E-07 erg/cm^2. The 16 ms peak photon flux measured
starting from T0-0.008 s in the 8-1000 keV band
is 20.5 +/- 1.3  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