Swift GRB Table

The Swift GRB Table contains the results from the initial analysis of Swift observations for each GRB triggered on board or GRB followed by Swift but triggered by different telescopes. The table contains results of the three Swift instruments: a) the hard wide-field X-ray Burst Alert Telescope (BAT), b) the focusing soft X-Ray Telescope (XRT), and c) the 30 cm UV-Optical Telescope (UVOT).

The Swift mission description is given in the Gehrels, N., et al. 2004 reference (2004ApJ...611.1005G).

Parameter Help Information

General

All general parameter values are typically from the values reported via the initial GCN circulars.

GRB (grb_name)

Name of the gamma-ray burst (GRB) given in a date format (YYMMDD). GRB names detected after 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 2010-01-01, letter order was only included if more than one burst candidate occurred in a single day.

Time (grb_time)

Trigger time of the Burst (UTC). If the burst is detected by Swift, the trigger time is from the Swift BAT instrument, else is from the first mission/instrument that detects the burst.

Trigger Number (grb_trigger)

The Swift Gamma-Ray Burst Trigger Number, if triggered by Swift. If not triggered by Swift the parameter is set to:
a) the mission(s) that detected the burst (e.g. "Fermi" or "FERMI", INTEGRAL");
b) "Ground Analysis" when discovered by the Swift ground analysis; and,
c) "GUANO" if detected by Gamma-ray Urgent Archiver for Novel Opportunities (GUANO) an automated system to download Swift BAT event data for triggers from different telescopes.

BAT Values

All Swift Burst Alert Telescope (BAT) parameter values are the values reported via the initail GCN circulars. Please see parameter "References" for further details.

BAT RA (bat_ra)

The Right Ascension of the Swift Burst Alert Telescope (BAT) detection (J2000) as reported in the first GCN circular associated to the Burst (see GCN BAT in the "References" paramter). Note: Because of the BAT's large field of view, this position may be different from other determinations. Also, for bursts that have Swift observations, but were not trigger by Swift BAT, this will be the RA determined by the detecting mission as reported via GCN circular.

BAT Dec (bat_dec)

The Declination of the Swift Burst Alert Telescope (BAT) detection (J2000) as reported in the first GCN circular associated to the Burst (see GCN BAT in the "References parameter). Note: Because of the BAT's large field of view, this position may be different from other determinations. Also, for bursts that have Swift observations, but were not trigger by Swift BAT, this will be the RA determined by the detecting mission as reported via GCN circular.

BAT 90% Error Radius (bat_err_radius)

The 90% confidence level radial position error (arcmin) of the Swift Burst Alert Telescope (BAT) burst coordinates.

BAT T90 (bat_t90)

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

BAT Fluence (bat_fluence)

The fluence (10^-7 erg/cm²) measured by Swift Burst Alert Telescope (BAT) from the Burst in the energy range 15-150 keV.

BAT Fluence 90% Error (bat_err_fluence)

The 90% confidence level fluence error (10^-7 erg/cm²) measured by Swift Burst Alert Telescope (BAT) from the Burst in the energy range 15-150 keV.

BAT 1-sec Peak Photon Flux (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 1-sec Peak Photon Flux 90% Error (bat_err_1s_peak_flux)

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

BAT Photon Index (bat_photon_index)

The power law photon index from the Swift Burst Alert Telescope (BAT) measured in the energy range 15-150 keV. If marked as "CPL", this is a cutoff power law index.

BAT Photon Index 90% Error (bat_err_photon_index)

The 90% confidence level error of the Swift Burst Alert Telescope (BAT) photon index parameter or the cutoff power law index.

XRT Values

Early (less than ~24 hours after the burst time) Swift X-Ray Telescope (XRT) values are the values reported via the initial GCN circulars. After 24 hours, values are updated with values sent from the XRT team (see: Evans et al., 2009, MNRAS, 397, 1177). Below is a brief explanation of their meaning and how they were derived:

XRT RA (xrt_ra)

The Right Ascension of the burst as determined by the Swift X-Ray Telescope (J2000). The XRT RA/Dec/Err are the "best" XRT position values available from one of the following options:

• Enhanced XRT position
• Unenhanced XRT ground position
• Enhanced XRT position from the prompt Single Pixel Event Report (SPER) data
• Position calculated onboard by XRT on first slewing to the burst.

XRT Dec (xrt_dec)

The Declination of the burst as determined by the Swift X-Ray Telescope (J2000). The RA/Dec/Err are the "best" XRT position values available from one of the following options:

• Enhanced XRT position
• Unenhanced XRT ground position
• Enhanced XRT position from the prompt Single Pixel Event Report (SPER) data
• Position calculated onboard by XRT on first slewing to the burst.

XRT 90% Error Radius (xrt_err_radius)

The 90% confidence radial position error (arcsec) in the burst location, as determined by the Swift X-Ray Telescope (XRT). The RA/Dec/Err are the "best" XRT position values available from one of the following options:

• Enhanced XRT position
• Unenhanced XRT ground position
• Enhanced XRT position from the prompt Single Pixel Event Report (SPER) data
• Position calculated onboard by XRT on first slewing to the burst.

XRT Time to First Observation (xrt_first_obs)

The time delay (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 (xrt_early_flux)

Flux of the burst source from the Swift X-Ray Telescope (XRT) in early observations (0.3-10 keV, units 10^-11erg/cm²/s). This flux estimate is from the Image mode and it is only available if there was an onboard XRT centroid. This is an estimate, not an exact measurament.

XRT 11 Hour Flux (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, units 10^-11erg/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 live online GRB catalogue; the number of breaks in the power-law is determined automatically.

XRT 24 Hour Flux (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, units 10^-11erg/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 live online GRB catalogue; the number of breaks in the power-law is determined automatically.

XRT Initial Temporal Index (xrt_lc_index)

The initial temporal index for the Swift X-Ray Telescope (XRT) detection of the burst source obtained by the decay index of the first segment of the fitted light curve.

XRT Spectral Index, Gamma (xrt_gamma)

The spectral index (gamma) for the Swift X-Ray Telescope (XRT) detection of the burst source obtained from an automated time-averaged (https://www.swift.ac.uk/xrt_spectra) spectral fit of the Photon Counting (PC) mode data. If the PC-mode data are not availble then the Window Timing mode data are used.

XRT Column Density, NH (xrt_nh)

The neutral hydrogen column density (nH 10²¹cm^-2) obtained from an auomated time-averaged spectral fit of the Swift X-Ray Telescope (XRT) burst data.

UVOT Values

All Swift Ultra-violet Optical Telescope (UVOT) paramater values are typically the values reported via the initial GCN circolars. Please see parameter "References" for further details.

UVOT RA (uvot_ra)

The Right Ascension of the burst source as observed by the Swift Ultra-violet Optical Telescope (UVOT) (J2000).

UVOT Dec (uvot_dec)

The declination of the burst source as observed by the Swift Ultra-violet Optical Telescope (UVOT) (J2000).

UVOT 90% Error Radius (uvot_err_radius)

The 90% confidence level in the radial position error (arcsec) of the Swift Ultra-violet Optical Telescope (UVOT) burst coordinates.

UVOT Time to First Observation (uvot_first_obs)

The time delay (seconds) between the initial burst detection and the start time of the first Swift Ultra-violet Optical Telescope (UVOT) observation of the source.

UVOT Magnitude (uvot_vmag)

The brightness, in stellar magnitude, of the visual (V band) Swift Ultra-violet Optical Telescope (UVOT) burst source.

UVOT Other Filter Magnitudes (uvot_filters)

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

Everything Else

The following paramter values are typically the values reported via GCN circular. Please see parameter "References" for further details.

Other Observatory Detections (other_obs)

A list of observatories that detected the burst, if any.

Ground Observations (grnd_obs)

A flag to indicate that the burst was observed by ground-based facilities.

Redshift (redshift)

The estimated redshift (z) of the burst location, and whether it was via spectral (emission or absorption) or photometric measurements.

Host (host)

Any apparent host galaxy information, if determined.

Comments (comments)

Any additional comments related to the burst.

References

Contains all the references for the various values in the table. These are broken down by reference type:

• BAT (ref_bat) - Reference(s) for the BAT source detection.
• XRT (ref_xrt) - Reference(s) for the XRT source detection.
• UVOT (ref_uvot) - Reference(s) for the UVOT source detection.
• Radio (ref_radio) - Reference(s) for any radio telescope observations of the source/burst.
• Redshift (ref_redshift) - Reference(s) for the determination of the redshift of the source/burst.
• Host (ref_host) - Reference(s) for the identification of the host galaxy.
• Other (ref_other) - Any other references related to the source/burst.

Burst Advocate (burst_advocate)

Name of the burst advocate assigned to the burst.