GCN Circular 1703
Subject
GRB021113, SPI ACS observation
Event
Date
2002-11-21T08:52:38Z (23 years ago)
From
Arne Rau at MPI <arau@xray.mpe.mpg.de>
A. Rau, V. Schoenfelder, A.v. Kienlin, G. Lichti G., N. Arend,
on behalf of the MPE INTEGRAL SPI-team;
J.-P. Roques on behalf of the Toulouse INTEGRAL
SPI-team;
J. Borkowski, R. Walter, N. Produit on behalf of the INTEGRAL Science Data
Center (ISDC) Geneve;
K. Hurley on behalf of the IPN team
report:
The Anticoincidence Shield (ACS) of the Spectrometer onboard the
INTEGRAL satellite (SPI) was switched on on the 26th of October 2002.
Since then, besides the major calibration and verification activities,
the ACS rates have already been monitored for GRBs. The ACS has
registered approximately 1 GRB per day, among them also the following
IPN-localized GRBs 021027 (GCN#1658), 021102 (GCN#1667) and 021108
(GCN#1679).
The first HETE-localized GRB detected by SPI ACS was GRB 021113
(=H2449; GCN #1686). The ACS lower energy threshold during this burst was
set to ~100 keV, but this threshold is broad; there exists no high-energy
threshold. GRB 021113 was seen in the total ACS rate (all 91 BGO crystals)
with 4 sigma on a 1s time scale.
The ACS lightcurve of GRB 021113
(http://www.mpe.mpg.de/gamma/instruments/integral/spi/acs/grb/021113_acs.html)
shows a single, smooth peak (similar to the HETE light curve), with a
maximum occuring at 6:38:58 UT. The absolute timing of the ACS is known
int the moment with an accuracy of ~100ms.
Continued "tuning" of the energy threshold and burst verification
algorithm is anticipated over the coming weeks, before the ACS will be
fully implemented into the INTEGRAL Burst Alert System (IBAS).
Acknowledgement is given to INTEGRAL Science Working Team for making these
burst data public.
This message is citable.