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GRBCAT: Help

GRBCAT - Gamma-Ray Bursts Catalog


Overview

This GRBs Catalog (GRBCAT) records high level information of the GRBs detected since their discovery in 1967. The catalog has been created using publications that report lists of GRB detections. These are mostly papers already published in refereed journals, unpublished papers, and PhD thesis presenting lists of GRBs. GRBCAT includes also compilation of bursts that were already present in the HEASARC database system. The catalog is organized with a main table reporting general information for each GRB and additional tables linked to the main table where specific information for the flux and the region of detection are reported. Afterglow measurements are also recorded in a separate table for all bursts detected after May 11 1996.

The main table for each GRB contains an entry for each satellite that reports a detection with either a flux and/or position measurement. Therefore for a given GRB there are multiple records if the GRB was detected by more than one satellite. The associated flux table contains an entry for each flux and fluence values reported in literature for a given energy band. The positional information is reported via different tables each dedicated to a specific region of detection. The region descriptions are the following : circle, annulus, box, dual, annulus intersect, irregular, and intersect.

The associated afterglow table contains position, intensity and redshift measurements taken after the discovery of the GRB. There are several records associated to a given GRB/afterglow since several observatories collected data on that position.

The main table and the associated tables are updated when a new GRB and/or afterglow measurements are reported.


References

References for the individual records in this table are available in the "reference" field of the GRBCAT main table.

Provenance

This table was ingested by the HEASARC in June 2008 based on electronic versions obtained from the author(s), who compiled the catalog in 2005.

Parameters

Record_Number
This is a numerical value that uniquely identifies a record within this database.

Id
This is a unique numerical value assigned to each GRB. Since for a given GRB there can be more that one record, this numerical value is assigned to all record associated to a specific GRB.

Name
This is the name of the GRB. The name are assigned following the "GRB YYMMDD" or "GRB YYMMDDn" if multiple bursts occur within a day, where n is a character string.

Alt_Names
This parameter contains alternative name used to identify the burst.

Time
This parameter contains the time when the GRB was observed (UT).

Time_Def
The time of a GRB occurrence has different definition depending on how has been detected. This field records a string related to the method of detection.

Observatory
Name of the observatory that detected the burst. If the observatory has more than one instrument capable of detecting GRB, this is reported with the following convention 'observatory-instrument'. If the detection of a GRB was determined by the contribution of different observatories, this is reported using the following convention 'observatory1/observatory2/...'.

RA
This is the Right Ascension of the center of the error region. There are seven different possible error regions.

Dec
This is the Declination of the center of the error region. There are seven different possible error regions.

Coord_Flag
This field is used to construct the name resolver for GRB. Value of -1 indicates the the GRB has not reported coordinates, 0 that there is only one set of coordinates and values ranging between 0-1 give a merit to the coordinates where higher number (closer to 1) are the best coordinates.

Region
This parameter contains the name of the region. The possible regions are: circle, annulus, box, dual, annulus intersect, irregular, intersect.

Afterglow_Flag
This is the Afterglow Flag. The parameter is set to 'Y', if the afterglow table includes afterglow measurements otherwise is set to 'N'.

Reference
Report the reference that report the GRB information in the table. It is given as ADS format.

T50_Mod
The T50 in literature is not always given as an exact value. This parameter records the symbol reported in literature for the approximation (<, >, ~, etc.).

T50
The 50% duration of the burst in seconds. T50 measures the duration of the time interval during which 50% of the total observed counts have been detected. The start of the T50 interval is defined by the time at which 25% of the total counts have been detected, and the end of the T50 interval is defined by the time at which 75% of the total counts have been detected.

T50_Error
This is the error of T50 (in seconds).

T50_Range
This is string that reports the Energy Range for T50 (in keV).

T50_Emin
The minimum of the energy range (in keV) for T50 gives as a numerical value.

T50_Emax
The maximum of the energy range (in keV) for T50 gives as a numerical value.

T90_Mod
The T90 in literature is not always given as an exact value. This parameter records the symbol reported in literature for the approximation (<, >, ~, etc).

T90
The 90% duration of the burst in seconds. T90 measures the duration of the time interval during which 90% of the total observed counts have been detected. The start of the T90 interval is defined by the time at which 5% of the total counts have been detected, and the end of the T90 interval is defined by the time at which 95% of the total counts have been detected.

T90_Error
This is the error of T90 (in seconds).

T90_Range
This is a string that reports the Energy Range for T90 (in keV).

T90_Emin
The minimum of the energy range (in keV) for T90 gives as a numerical value.

T90_Emax
The maximum of the energy range (in keV) for T50 gives as a numerical value.

T_Other
For some of the GRBs the duration is not provided as either T50 or T90. The parameter "t_other" contains the duration, in seconds, obtained using different methods. In many cases the measurement is not exact. If that occurs, the note field contains more information on the duration, as well as the energy range if enabled.

Flux_Flag
This is the Flux Flag. The parameter is set to 'Y', if the flux table includes flux measurements, otherwise is set to 'N'.

Notes
This field contains general note on the GRB.

Flux_Notes
This field contains notes on the flux or fluence measurements. This is filled only when the data taken from literature do not match the fields in the database and additional explanation is required.

Local_Notes
This field contains notes regarding the localization of the GRB. This is filled to explain how the values reported in the database are compared with the values reported in the literature.

Class
Browse object classification. All objects are currently classified as GRB.


Contact Person

Questions regarding the GRBCAT database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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