SWIFTGRBBA - Swift Gamma Ray Burst Compilation by Burst Advocate

Overview

This database table includes the early results published in the Gamma-Ray Burst Coordinates Network (GCN) circulars on GRBs detected by the Swift observatory and GRBs detected first by other observatories and followed by Swift. The Swift observatory has a rapid (minute timescale) response to GRB detection and performs sensitive X-ray and optical afterglow observations of hundreds of GRBs on all timescales, from minutes to even months later.

The instrumentation consists in a large field of view (FOV) instrument, the Burst Alert Telescope (BAT, 15-150 keV) and two narrow field of view instruments, the Ultraviolet/Optical Telescope (UVOT) and the X-ray Telescope (XRT). The BAT searches the sky for gamma-ray bursts (GRBs), determines their location with a precision of a few arcminutes, and triggers an autonomous spacecraft slew to place the burst in the FOV of the narrow field instruments. The first-look data from the three Swift instruments for a newly discovered GRB and its afterglow are transmitted to the ground via TDRSS. The complete telemetry (including the messages transmitted via TDRSS) is subsequently sent down via the Malindi ground station.

The information transmitted via TDRSS are broadcast via the the Gamma-Ray Burst Coordinates Network (GCN) followed by subsequent GCN circular based on the early ground analysis of the data collected by Malindi. If the GRB is triggered by Swift , this table records the initial characteristic associated to a burst obtained with the data coming via TDRSS and initial data downloaded via Malindi which results are published via the GCN. In addition the table reports other burst characteristics as for redshift obtained by observations with ground observatories.

If the GRB is detected first by other observatories, the table reports results obtained with the ground analysis of the Malindi data and published via the GCN.

Catalog Bibcode

2004ApJ...611.1005G

Bulletin

The SWIFTGRBBA database table was last updated on 2 February 2026.

References

The Swift Gamma-Ray Burst Mission
    Gehrels, N., et al.,  Astrophysical Journal Volume 611, Issue 2,
    pp. 1005-1020 (2004).
   =2004ApJ...611.1005G

Provenance

This database table is generated by compiling the results of the GCN circulars. It was added to the HEASARC database in March 2025. During operation, it is updated weekly and/or for any new trigger. This table is also available at https://swift.gsfc.nasa.gov/archive/grb_table/.

Parameters

Name
Designation of the gamma-ray burst (GRB) given in a date format (YYMMDD) to indicate when it was detected. GRBs since 2010-01-01 also always include a letter indicating the temporal order in which they were detected: A for the first burst in a day, B for the second, and so on. For bursts prior to 2010-01-01, letter order was only included if more than one burst candidate occurred in a single day.

Trigger_Time
Time of the burst (UTC) as reported in the GCN circular.

Time
This contains the date/time (UTC) of the burst, converted to Modified Julian Date (MJD) format. This parameter has been added by the HEASARC and is derived from the YYMMDD date from the GRB's name and the trigger_time parameter.

Trigger_Obs
The name of the observatory which instruments first reported the trigger. If the parameter contains the string "Ground Analysis" or "GUANO", that indicates that the results are from ground analysis of the Swift data. The parameter may contain more than one observatory.

Target_ID
The Swift Gamma-Ray Burst Trigger Number, if triggered by Swift. The field is empty if the trigger is coming other observatories.

RA
The Right Ascension of the Swift Burst Alert Telescope (BAT) detection as shown in the matching BAT reference. Note: Because of the BAT's large field of view, this position may be different from other determinations. If the GRB is not triggered by Swift BAT, the parameter has the right ascension determined by the detecting mission as reported via GCN circular. This is given in the J2000 equinox in the original data.

Dec
The Declination of the Swift Burst Alert Telescope (BAT) detection as shown in the matching BAT reference. Note: Because of the BAT's large field of view, this position may be different from other determinations. If the GRB is not triggered by Swift BAT, the parameter has the declination determined by the detecting mission as reported via GCN circular. This is given in the J2000 equinox in the original data.

LII
The Galactic longitude of the GRB detection. This parameter has been added by the HEASARC and is derived from the J2000.0 source position.

BII
The Galactic latitude of the GRB detection. This parameter has been added by the HEASARC and is derived from the J2000.0 source position.

Error_Radius
The 90%-confidence radial position uncertainty (in arcmin) of the Swift BAT burst detection coordinates.

BAT_T90
The time interval (in seconds) in which 90% of the fluence was detected by Swift Burst Alert Telescope (BAT).

BAT_Fluence
The fluence (in erg/cm²) measured by Swift Burst Alert Telescope (BAT) from the burst in the energy range 15-150 keV.

BAT_Fluence_Error
The 90%-confidence uncertainty (in erg/cm²) in the measured BAT fluence in the energy range 15-150 keV.

BAT_1s_Peak_Flux
The 1-second peak photon flux (photon/cm2/s) measured by Swift Burst Alert Telescope (BAT) from the Burst in the energy range 15-150 keV.

BAT_1s_Peak_Flux_Error
The 90% confidence level error (photon/cm2/s) of the Swift Burst Alert Telescope (BAT) 1-second peak photon flux parameter.

BAT_Spectral_Model
Model used to fit the BAT spectra. This is either to "PL" for power law model and "CPL" for cut-off power law model.

BAT_Photon_Index
The power law photon index from the Swift Burst Alert Telescope (BAT) spectra measured in the energy range 15-150 keV for the model indicated by the bat_spectral_model parameter.

BAT_Photon_Index_Error
The 90%-confidence uncertainty of the BAT power law photon index.

XRT_RA
The Right Ascension of the burst as determined by the Swift X-Ray Telescope as shown in the XRT reference. This is the "best" XRT position values available from one of the following options: a) enhanced XRT position, b) unenhanced XRT ground position, c) enhanced XRT position from the prompt Single Pixel Event Report (SPER) data, and d) Position calculated on-board by XRT on first slewing to the burst. This is given in the J2000 equinox in the original data.

XRT_Dec
The Declination of the burst as determined by the Swift X-Ray Telescope as shown in the XRT reference. This is the "best" XRT position values available from one of the following options: a) enhanced XRT position, b) unenhanced XRT ground position, c) enhanced XRT position from the prompt Single Pixel Event Report (SPER) data, and d) Position calculated on-board by XRT on first slewing to the burst. This is given in the J2000 equinox in the original data.

XRT_Error_Radius
The 90%-confidence radial position uncertainty (in arcsec) in the burst location, as determined by the Swift X-Ray Telescope. This is the "best" XRT position values available from one of the following options: a) enhanced XRT position, b) unenhanced XRT ground position, c) enhanced XRT position from the prompt Single Pixel Event Report (SPER) data, and d) Position calculated on-board by XRT on first slewing to the burst.

XRT_First_Obs
The time delay (in seconds) between the initial burst detection and the start time for the first Swift X-Ray Telescope (XRT) observation. The XRT start time is taken either from the GCN Notice containing the XRT position "ACK" or "NACK" or if the ACK or NACK are not available from the XRT start time is taken from the first packet of Single Pixel Event Report (SPER).

XRT_Early_Flux
Flux of the burst source from the Swift X-Ray Telescope (XRT) in early observations (0.3-10 keV, in erg/cm²/s). This flux estimate is from the Image mode and it is only available if there was an on-board XRT centroid. This is an estimate, not an exact measurement.

XRT_11hr_Flux
Flux of the burst source from the Swift X-Ray Telescope (XRT) during the first 11 hours after detection (0.3-10 keV, in erg/cm²/s). The flux is derived by fitting a (broken) power-law model to the light curve, extrapolating to 11 hours, and applying a counts-to-flux conversion from the spectral fit. The value is taken from the table at https://www.swift.ac.uk/xrt_live_cat/, which reports results on an automatic unsupervised analysis. The number of breaks in the power-law is determined automatically.

XRT_24hr_Flux
Flux of the burst source from the Swift X-Ray Telescope (XRT) during the first 24 hours after detection (0.3-10 keV, in erg/cm²/s). The flux is derived by fitting a (broken) power-law model to the light curve, extrapolating to 24 hours, and applying a counts-to-flux conversion from the spectral fit. The value is taken from the table at https://www.swift.ac.uk/xrt_live_cat/, which reports results on an automatic unsupervised analysis. The number of breaks in the power-law is determined automatically.

XRT_Lc_Index
The XRT temporal decay index obtained by fitting the first segment of the XRT lightcurve.

XRT_Gamma
The XRT spectral index (gamma) of the burst obtained from an automated spectral fitting of the time-averaged spectrum obtained with the Photon Counting (PC) mode data or Window Timing data. The time-averaged spectrum is obtained with observations which begin within 12 hours of the first XRT observation on source. (See https://www.swift.ac.uk/xrt_spectra/.)

XRT_NH
The neutral hydrogen column density (nH, in cm^-2) obtained from the automated spectral fitting of the time-averaged spectra.

UVOT_RA
The Right Ascension of the burst source as observed by the Swift Ultraviolet Optical Telescope (UVOT) as shown in the UVOT reference. This is given in the J2000 equinox in the original data.

UVOT_Dec
The declination of the burst source as observed by the Swift Ultraviolet Optical Telescope (UVOT) as shown in the UVOT reference. This is given in the J2000 equinox in the original data.

UVOT_Error_Radius
The 90%-confidence radial position uncertainty (in arcsec) for the Swift Ultraviolet Optical Telescope (UVOT) burst detection.

UVOT_First_Obs
The time delay (in seconds) between the initial burst detection and the start time for the first Swift X-Ray Telescope (XRT) observation.

UVOT_Vmag_Flag
This parameter is set to 1 if the vmag is an upper limit.

UVOT_Vmag
The brightness, in stellar magnitude, of the visual (V band) UVOT burst source.

UVOT_Mag
The brightness, in stellar magnitude, of the Swift Ultraviolet Optical Telescope (UVOT) filters settings other than V, if observed. The possible filters are B, U, UVW1, UVW2, UVM2 and White.

Other_Obs
A list of the other observatories that followed the burst.

Redshift
The estimated redshift (Z) of the burst location.

Redshift_Comment
The parameter reports whether the redshift was obtained via spectral (emission or absorption) or photometric measurements. Not always present.

Other_Redshift
This parameter reports other measurements for the redshift.

Host_Galaxy
This parameter reports any apparent host galaxy, if determined.

Comment
Other specific comments on the burst.

Ref_Bat
Reference(s) for the BAT source detection and observational characteristics.

Ref_XRT
Reference(s) for the XRT source detection and observational characteristics.

Ref_Uvot
Reference(s) for the UVOT detection and observational characteristics.

Ref_Radio
Reference(s) for any radio telescope observations of the burst.

Ref_Redshift
Reference(s) for the determination of the redshift of the burst.

Ref_Host
Reference(s) for the identification of the host galaxy.

Ref_Other
Any other references related to the burst.

Advocate
The name of the "burst advocate." This is the scientist that followed the initial burst observation.

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: Monday, 17-Mar-2025 17:40:00 EDT