[vsnet-grb-info 13890] GRB 130907A: INTEGRAL/SPI-ACS light curve

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15204
SUBJECT: GRB 130907A: INTEGRAL/SPI-ACS light curve
DATE:    13/09/09 15:33:25 GMT
FROM:    Volker Beckmann at APC  <beckmann at apc.univ-paris7.fr>

V. Savchenko, V. Beckmann (APC), C. Ferrigno, E. Bozzo, M. Beck (ISDC),
J. Borkowski (CAMK/Torun), D. Götz (CEA/Saclay), S. Mereghetti (INAF/IASF-Milano), A. von Kienlin, A. Rau  (MPE), and K. Hurley (SSL/Berkeley)

GRB 130907A, detected by Swift/BAT (Palmer et al. GCN 15183), Fermi/LAT (Vianello et al. GCN 15196) and Konus-Wind (Frederiks et al, GCN 15203), has been independently detected by the SPI Anti-Coincidence System (ACS) on-board INTEGRAL. The SPI-ACS light curve reveals the rich multi-peak structure of this burst starting at 2013-09-07T21:39:16. Several bright peaks are followed by a major activity episode at about T0+100s. The maximum count-rate of 94,000 counts/sec (approximately corresponding to 1e-5 erg/cm2/s in the 75 keV-1 MeV range, Vigano and Mereghetti 2009) over the time bin length of 50 msec is reached at T0+115s. The total duration of this GRB is
about 250 seconds.

The SPI-ACS light curve of this GRB is available at:
http://www.isdc.unige.ch/integral/ibas/cgi-bin/ibas_acs_web.cgi/?trigger=2013-09-07T21-39-16.00-00000-00000-0

All SPI-ACS light curves are available (both as images and data files) at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi.
The light curves, binned at 50 ms, are derived from 91 independent detectors with different lower energy thresholds (mainly between 50 keV and 150 keV). SPI-ACS has no upper energy threshold and can detect photons with energies up to at least 100 MeV. The ACS response varies as a function of the GRB incident angle. For these reasons we caution that the count rates cannot be easily translated into physical flux units.