GCN Circular 13498
Subject
GRB 120716A: Fermi GBM observation
Date
2012-07-20T11:21:05Z (12 years ago)
From
David Gruber at MPE <dgruber@mpe.mpg.de>
David Gruber (MPE) and Adam Goldstein (UAH)
report on behalf of the Fermi GBM Team:
"At 17:05:03.91 UT on 16 July 2012, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 120716A (trigger 364151106 / 120716712).
This burst was localized by the IPN (Hurley et al., GCN 13487).
The GBM on-ground calculated location is consistent with the
IPN location.
The angle from the Fermi LAT boresight is 63 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of a bright precursor, followed
by a double-peaked main emission after ~ 160 s.
The duration (T90) is about 234 s (50-300 keV).
The time-averaged spectrum of the precursor is best fit by
a power law function with an exponential
high-energy cutoff. The power law index is -0.84 +/- 0.11 and
the cutoff energy, parameterized as Epeak, is 173 +/- 18 keV.
A Band function fits the spectrum equally well
with Epeak= 115 +/- 19 keV, alpha = -0.48 +/- 0.22 and beta = -2.19 +/- 0.17.
The time-averaged spectrum of the main emission is best fit by
a Band function with Epeak= 114 +/- 12 keV, alpha = -1.00 +/- 0.08
and beta= -2.08 +/- 0.07.
The event fluence (10-1000 keV) is (1.47 +/- 0.01)E-05 erg/cm^2.
The 1-sec peak photon flux measured starting from T0-0.13 s
in the 10-1000 keV band is 8.37 +/- 0.32 ph/s/cm^2.
Using the redshift of 2.48 (Greiner et al., GCN 13493; D'Elia et al., GCN 13494)
and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27,
Omega_Lambda = 0.73, this corresponds to an isotropic
energy release of ~ 3E+53 erg.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."