GCN Circular 9424
Subject
GRB 090524: Fermi GBM detection
Date
2009-05-26T15:20:47Z (16 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) report on behalf of the Fermi GBM Team:
"At 08:17:56.23 UT on 24 May 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090524 (trigger 264845878 / 090524346).
The on-ground calculated location, using the GBM trigger
data, is RA = 329.5, DEC = -67.4 (J2000 degrees,
equivalent to 21h 58m, 67d 24'), 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 63 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of two main pulses
with a duration (T90) of about 72 s (8-1000 keV).
The time-averaged spectrum from T0+0.003 s to T0+71.681 s is
best fit by a Band function with Epeak = 82.6 +/- 6.3 keV,
alpha = -1.00 +/- 0.08, and beta = -2.30 +/- 0.09
(chi squared 959 for 840 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(1.85 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+5.120 s in the 8-1000 keV band
is 14.1 +/- 1.4 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."