[vsnet-grb-info 7964] GRB 090610: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9507
SUBJECT: GRB 090610: Fermi GBM detection
DATE:    09/06/12 16:27:36 GMT
FROM:    Adam Goldstein at Fermi-GBM/UAH  <adam.m.goldstein at 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."