[vsnet-grb-info 8308] GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9833
SUBJECT: GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
DATE:    09/08/24 06:34:33 GMT
FROM:    Sandip K. Chakrabarti at S.N. Bose Nat. Centre for Basic Sci.  <chakraba at bose.res.in>

GRB 090820: RT-2 detection of a strong burst


S. K. Chakrabarti, A. Nandi, D. Debnath, T. C. Kotoch (ICSP, Kolkata, 
India), A. R. Rao, J. P. Malkar, M. K. Hingar, V. K. Agrawal (TIFR, Mumbai, 
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 detected GRB 
090820 (FERMI, Trigger No.- 272421498, V. Connaughton, GCN 9829) which 
is     triggered at T0 = 00h 38m 16s (UT) (Onboard processor switch/toggle 
to Flare mode from Quiet mode). The satellite was in the GOOD/LIGHT mode  
with Earth latitude = -64.09 and longitude = 169.11. with GOOD time 
observation of 600 sec starting at 00h 29m 16sec (UT) and ending at 00h 39m 
16sec (UT). After 30 sec, the satellite completely entered into BAD mode of 
high charge particle region.

The GRB light curve shows a simple profile of a strong emission peak at 
T0+34 sec with a weak precursor (T0). The time duration of the brightest 
emission is around 19 sec with ~1100 cts/sec.
 
Both RT-2/S and RT-2/G detectors have registered this burst profile in the 
energy band of 15 - 1000 keV with strongest emission in the energy range of 
above 100 keV to 330 keV. It is also noted that the burst width decreases 
with the increase in the energy band, a quite natural phenomena of GRB burst 
profile. 

This analysis is preliminary. Analysis of time resolved spectral data is 
going on, however
the light curve is available at the web-site: 
http://csp.res.in/rt2_files/grb090820-lc.html