[vsnet-grb-info 8132] Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9665
SUBJECT: Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
DATE:    09/07/15 08:23:22 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba at bose.res.in>

Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite


A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, India), S. K. 
Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, India), T. R.
Chidambaram, P. Vinod, S. Sreekumar (VSSC, Thiruvananthapuram, India), Y. D.
Kotov, A. S. Buslov, V. N. Yurov, V. G. Tyshkevich, A. I. Arkhangelskij, R. A.
Zyatkov (MephI, Moscow, Russia) report:

The RT-2 Experiment onboard the CORONAS-PHOTON satellite has clearly detected
GRB 090618 (Schady et al., 2009, GCN 9512) which triggered at T0 = 30507.00
sec (UT) (08h 28m 27s). The satellite was in the SHADOW mode (away from the
SUN) with GOOD time (away from the polar and SAA regions) observation of 700
sec starting at 08h 23m 27sec (UT) and ending at 08h 36m 46.99sec (UT).

The GRB light curve shows a complex profile (Golenetskii et al., 2009, GCN 
9553) of time duration of around 150 sec. The burst profile has three main 
pulses with the brightest pulse (~700 cts/sec) started at T0+65 sec, the second 
one at T0+85 sec and the last one at T0+115 sec.

Both RT-2/S and RT-2/G detectors have registered this multi-structured burst 
profile of the light curve in the energy band of 60 - 215 keV. In high-energy 
band of 330 - 1000 keV, the profile becomes simple with a single bright peak at 
T0+65 sec. It is also noted that the burst width decreases with the increase in 
the energy band, a quiet natural phenomena of GRB burst profile. The burst was 
incident at an angle of 77 degrees to the detector axis. It showed the typical 
Band spectrum with peak energy at about 180 keV and integrated 20 keV - 1MeV
flux of 2.8 X 10^-4 ergs/ cm^2.
 
The light curve is available at the web-site:
http://csp.res.in/rt2_files/grb090618-lc.html