GCN Circular 11952

Subject

GRB 110420B: Fermi GBM observation

Event

Date

2011-04-21T13:55:31Z (15 years ago)

From

Lin Lin at UAH/NAOC <ll0005@uah.edu>

Lin Lin (UAH)
reports on behalf of the Fermi GBM Team:

"At 22:42:11.73 UT on 20 April 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110420B (trigger 325032133 / 110420946).

This burst was also detected by the Swift/BAT
(Sbarufatti et al. 2011, GCN 11944Loading...
 
 ).
The GBM on-ground location is consistent with the Swift position.
The angle from the Fermi LAT boresight is 123 degrees.

The GBM light curve shows a fast rise slow decay peak,
with a duration (T90) of about 0.048 s (50-300 keV).
The time-averaged spectrum from T0-0.024 s to T0+0.040 s is
well fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.12 +/- 0.31 and
the cutoff energy, parameterized as Epeak, is 296.8 +/- 58.7 keV.

The event fluence (10-1000 keV) in this time interval is
(2.65 +/- 0.36)E-7 erg/cm^2. The 0.008-sec peak photon flux measured
starting from T0-0.016 s in the 10-1000 keV band
is 44.1 +/- 6.1 ph/s/cm^2.

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