GUSBAD - GRBs Uniformly Selected from BATSE Archival Data

Overview

The GUSBAD (Gamma-ray bursts Uniformly Selected from BATSE Archival Data) Catalog is based on BATSE DISCLA data at a time resolution of 1.024 seconds for the full 9.1 years of the Compton Gamma-Ray Observatory (CGRO) mission from April 19, 1991 until May 26, 2000 (corresponding to Truncated Julian Dates from 8365 to 11690). This catalog lists over 2200 gamma-ray bursts (GRBs).

Selection of GRBs for the GUSBAD Catalog requires a 5-sigma excess over the background in two of the BATSE detectors over the energy range 50-300 keV. The search covers the entire mission except when CGRO was over particular geographic regions or during one of 199,964 time windows when DISCLA data were missing or contaminated. The classification as GRB or non-GRB of the 6236 events that were produced by the software trigger was aided by correlating the times and positions of the events against the Current BATSE Burst Catalog. There are 589 GRBs in the GUSBAD Catalog that are not included in the Current BATSE Burst Catalog.

The GUSBAD catalog is uniform in the sense that the detection criterion is the same throughout and that the properties given in the catalog are available for every burst. The detection and the derivation of the properties listed in the catalog were carried out automatically, except for some rare instances. This makes the catalog especially suitable for statistical work and simulations, such as used in the evaluation of V/Vmax. The procedure used to detect and classify the bursts has been described in Schmidt (2004).

Catalog Bibcode

2004ApJ...616.1072S

References

              Schmidt, M. 2004, ApJ, 616, 1072

Provenance

This database table was last updated by the HEASARC in April 2005 using the file GUSBADcat.dat containing version 2.1 of the catalog, which was obtained from the catalog author's web site at http://www.astro.caltech.edu/~mxs/grb/GUSBAD/

Comments or questions about the contents of the GUSBAD Catalog are welcomed by the author who can be contacted at mxs@astro.caltech.edu.

Latest Version

According to the description on the author's web site, the current version of GUSBAD has the following changes compared to the previous version:

Version 2.1 - Apr 20, 2005  Software error in the evaluation of
                            scattered radiation corrected, leading to
                            rms changes in all positions (3 deg),
                            peak_flux (5%), fluence (2%), spectral_index
                            (0.01), angle_1 (1 deg) and angle_2 (1 deg).
                            Three GRBs were dropped, and six GRBs were
                            added for a new total of 2207 GRBs.

Parameters

Name
The gamma-ray burst designation in the form 'GUSBAD YYMMDD.ddd', using the prefix 'GUSBAD ' and the date and time of the burst to a precision of 0.001 days, e.g., 'GUSBAD 000101.055' is the name of the burst which occurrred on 2000 Jan 01 at about 01:20 UT.

Day_GRB
The Truncated Julian Date (TJD) of the trigger (JD - 2440000.5).

Seconds_GRB
The seconds of day (UT) of the trigger since the beginning of the day specified by the day_grb parameter. This was given to a precision of 1 second in the original table.

Time
The gamma-ray burst trigger time (UT) in the HEASARC's standard time representation, computed using the day_grb and seconds_grb parameter values.

RA
The Right Ascension of the GRB in the selected equinox. This was given in degrees to a precision of 1 degree in the original table.

Dec
The Declination of the GRB in the selected equinox. This was given in degrees to a precision of 1 degree in the original table.

LII
The Galactic Longitude of the GRB.

BII
The Galactic Latitude of the GRB.

Error_Radius
The rms deviation from the mean of the individual positions derived from the 1.024-s intervals that were used for the position derivation (num_int_pos), in degrees. This parameter was given to a precision of 1 degree in the original table.

Num_Int_Pos
The number of 1.024-s intervals that were used for the position derivation.

Ptop
The data packet number (p-number) corresponding to the time of the maximum burst signal (when the count rate is equal to c_max), on a scale where the p-number corresponding to the trigger time is 301.

Plast
The data packet number (p-Number) corresponding to the last time that the burst signal exceeded the trigger limit, on a scale where the p-number corresponding to the trigger time is 301.

V_Upon_Vmax
The V/Vmax value for the burst based on a simulation in which the burst is moved outwards in Euclidean space until it is below the trigger limit.

Pfar
The p-number of the final burst signal at the detection limit in the V/Vmax simulation of the burst.

GRB_Class
This flag parameter is set to B to indicate that the classification of the event as a GRB was partly based on its appearance in the Current BATSE Burst Catalog, while it is set to G to indicate that the classification was made independently of other catalogs.

C_Max
The maximum count rate for the burst signal in the second most brightly illiminated detector, Detector_2, in counts/s.

C_Min
The minimum count rate needed for a trigger to have occurred in the second most brightly illuminated detector, Detector_2, in counts/s.

Peak_Flux
The peak flux of the burst (counts/cm²/s).

Fluence
The fluence of the burst (counts/cm²).

Num_Int_Trig
The number of 1.024-s time intervals when the burst exceeded the trigger limit.

Hardness_Ratio_1
The hardness ratio obtained from the ratio of counts in the BATSE channel 1 (20-50 keV) to the summed counts of channels 2 and 3 (50-300 keV).

Hardness_Ratio_2
The hardness ratio obtained from the ratio of counts in the BATSE channel 2 (50-100 keV) to the summed counts of channels 2 and 3 (50-300 keV).

Hardness_Ratio_3
The hardness ratio obtained from the ratio of counts in the BATSE channel 3 (100-300 keV) to the summed counts of channels 2 and 3 (50-300 keV).

Hardness_Ratio_4
The hardness ratio obtained from the ratio of counts in the BATSE channel 4 (>300 keV) to the summed counts of channels 2 and 3 (50-300 keV).

Spectral_Index
The photon spectral index for the burst corresponding to the count ratio of channel 3 (100-300 keV) to channel 2 (50-100 keV).

Azimuth
The azimuth of the burst (degrees).

Altitude
The altitude of the burst (degrees).

BATSE_Azimuth
The azimuth of the burst in the BATSE-based coordinate system (degrees).

BATSE_Altitude
The altitude of the burst in the BATSE-based coordinate system (degrees).

Detector_1
The identification of the most brightly illuminated detector.

Angle_1
The angle between the normal direction to Detector_1 and the direction of the GRB (degrees).

Detector_2
The identification of the second most brightly illuminated detector.

Angle_2
The angle between the normal direction to Detector_2 and the direction of the GRB (degrees).

Contact Person

Questions regarding the GUSBAD database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:28:32 EDT