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INTSPIAGRB - INTEGRAL First SPI-ACS Gamma-Ray Burst Catalog

HEASARC
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Overview

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.


Catalog Bibcode

2005A&A...438.1175R

References

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)

Provenance

This table was created by the HEASARC in October 2005 based on CDS table J/A+A/438/1175/table2.dat .

Parameters

Sequence_Number
A unique identifying number for the event.

Name
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'.

Time
The trigger date and time in UTC, given to the nearest second.

Significance
The maximum significance of the event above the background, in terms of sigma.

Duration
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.

Duration_Error
The uncertainty in the t_90 duration, in seconds.

Counts
The total integrated counts in the event, in kilocounts (kct).

Counts_Error
The RMS uncertainty in the integrated counts, in kct.

Max_Count_Rate
The peak count rate over a 0.25 seconds interval, in kct/0.25s.

Max_Count_Rate_Error
The RMS uncertainty in the peak count rate, in kct/0.25s.

V_Upon_Vmax
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.

Var045_Measure
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.

Var045_Measure_Error
The RMS uncertainty in the variability measure.

Confirmation
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
  

Contact Person

Questions regarding the INTSPIAGRB database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 5-Mar-2013