GCN Circular 9507
Subject
GRB 090610: Fermi GBM detection
Date
2009-06-12T16:27:36Z (16 years ago)
From
Adam Goldstein at Fermi-GBM/UAH <adam.m.goldstein@msfc.nasa.gov>
A. Goldstein (UAH) reports on behalf of the Fermi GBM Team:
"At 15:33:25.94 UT on 10 June 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090610 (trigger 266340807 / 090610648).
The on-ground calculated location, using the GBM trigger
data, is RA = 84.2, DEC = 35.4 (J2000 degrees,
equivalent to 05h 37m, 35d 224'), with an uncertainty
of 5.2 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 70 degrees.
This burst was also independently detected by INTEGRAL SPI-ACS.
The GBM light curve consists of one main pulse
with a duration (T90) of about 6.5 s (8-1000 keV).
The time-averaged spectrum from T0-3.1 s to T0+3.2 s is
best fit by a simple power law function with index -1.30 +/- 0.03
(chi squared 621.1 for 606 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(7.32 +/- 0.24)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.51 s in the 8-1000 keV band
is 0.94 +/- 0.09 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."