INTSPIAGRB - INTEGRAL First SPI-ACS Gamma-Ray Burst Catalog
The First INTEGRAL SPI-ACS Gamma-Ray Burst (GRB) Catalog contains
the sample of gamma-ray bursts detected with the Anti-Coincidence Shield
(ACS) of the SPI spectrometer on-board the INTEGRAL spacecraft for the
first 26.5 months of mission operations (up to January 2005). The SPI-ACS
works as a nearly omnidirectional gamma-ray burst detector above ~80 keV,
but it lacks spatial and spectral information. In this catalog, the
properties derived from the 50 millisecond (ms) light curves (e.g.,
T_90, C_max, C_int, variability, and V/V_max) are given for each
candidate burst in the sample. A strong excess of very short events
with durations < 0.25 seconds is found. This population is shown to be
significantly different from the short- and long-duration burst sample
by means of the intensity distribution and the V/V_max test and is
certainly connected with cosmic ray hits in the detector. A rate of
0.3 true gamma-ray bursts per day is observed.
This table lists the properties of 388 GRB candidates detected from Oct 27,
2002 to Jan 15, 2005 with the Anti-Coincidence Shield (ACS) of SPI.
It has numerous events with missing entries, notice. For all GRBs which were
confirmed by other instruments but were detected by SPI-ACS below the sample
selection threshold, only the time, date, significance and common instruments
are listed. Furthermore, the variability measure was obtained only for
long-duration events which had sufficiently large signal-to-noise ratios.
A continuously updated on-line version of the GRBs observed by SPI-ACS is
available at http://www.mpe.mpg.de/gamma/science/grb/1ACSburst.html
and includes figures and ASCII files of the light curves.
The 1st INTEGRAL SPI-ACS Gamma-Ray Burst Catalogue.
Rau A., Kienlin A. von, Hurley K., Lichti G.G.
<Astron. Astrophys. 438, 1175 (2005)>
=2005A&A...438.1175R (SIMBAD/NED BibCode)
This table was created by the HEASARC in October 2005 based on
CDS table J/A+A/438/1175/table2.dat .
A unique identifying number for the event.
The event designation based on the date on which it occurred. The
HEASARC has constructed this parameter by adding a 'GRB ' prefix to the
YYMMDD date listed in the published table, and an 'a', 'b', etc., suffix
if multiple GRBs occurred on the same day. Thus, the second burst which
occurred on 2002 Nov 25 has been given the name of 'GRB 021125b'.
The trigger date and time in UTC, given to the nearest second.
The maximum significance of the event above the background,
in terms of sigma.
The observer frame duration of the event, t_90, in seconds.
This is the time interval over which the burst emitted from 5% to 95% of
its total measured counts.
The uncertainty in the t_90 duration, in seconds.
The total integrated counts in the event, in kilocounts (kct).
The RMS uncertainty in the integrated counts, in kct.
The peak count rate over a 0.25 seconds interval, in
The RMS uncertainty in the peak count rate,
The V/Vmax statistic for the event. V/Vmax compares the
volume in which the event was detected to the largest possible volume
in which the event would be just at the detection threshold. See
the Schmidt M., 1968ApJ...151..393S for more details.
The variability measure for the event. The variability
V(f=0.45) was computed from the variance of the 50 ms binned light curve
with respect to a boxcar-smoothed version of itself following the
formulation of Reichart et al. (2001ApJ...552...57R). A smoothing timescale
of t_0.45, the effective time for which the integrated counts of the
brightest part of the event comprise 45% of the total counts, was used.
The RMS uncertainty in the variability measure.
This parameter contains flags which identify all other
gamma-ray instruments and missions for which detections of the event were
reported. The designations of the other instruments are as follows:
U = Ulysses
K = Konus/Wind
M = Mars-Odyssey
H = HETE-2
R = RHESSI
C = Helicon/Coronas-F
I = INTEGRAL (SPI/IBIS)
S = Swift
X = RXTE/ASM
Questions regarding the INTSPIAGRB database table can be addressed to the
HEASARC User Hotline.
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