BATSEGRB - CGRO/BATSE Gamma-Ray Burst Catalog
All BATSE trigger data from the CGRO mission are available through this facility. As part of a final archiving effort, the BATSE instrument team is making minor refinements to certain data products. These revised products will be delivered to the HEASARC as soon as they are produced and tested. Certain burst catalog parameters, notably the position information, may be revised through improved analyses and instrumental calibration. The final catalog will be posted here as soon as it is completed.
The BATSE Current Gamma-Ray Burst Catalog, the BATSE GRB Team, http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/ The Fourth BATSE Gamma-Ray Burst Catalog, C. A. Meegan et al., in "Gamma-Ray Bursts: the Fourth Huntsville Symposium (IAP No. 428)", ed. Meegan, C.A., Preece, R.D. and Koshut, T.M., p. 1. (1997). The Third BATSE BATSE Gamma-Ray Burst Catalog, C. A. Meegan et al., ApJS, 106, 65. (1996).
BATSE Current Gamma-Ray Burst Catalog: http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/ Some flux and fluence data and all the comments are from the BATSE 4B Catalog: http://gammaray.msfc.nasa.gov/batse/grb/catalog/4b/
This database table was first created at the HEASARC in June 2001. The HEASARC version is automatically updated within one week of whenever the data files located at http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/ are changed.
Naming Convention Contents tte_bfits_YYYY.fits time-sequenced 4-energy channel data bracketing trigger; combines discla, preb, discsc, and tte. discsc_bfits_YYYY.fits time-sequenced 4-energy channel data bracketing time of burst trigger for triggered detectors; combines data types discla, preb and discsc. (s)her_bfits_X_YYYY.fits time-sequenced 128 energy channel data bracketing time of burst trigger for specified detector; combines datatypes her and herb - suggested data type for 128 energy channel burst analysis. mer_bfits_YYYY.fits time-sequenced 16-energy channel data for times bracketing burst trigger - triggered detectors only; combines mer and cont datatypes - suggested for 16-energy channel burst analysis. discsc_drm_YYYY.fits detector response matrix for 4 energy channel burst data triggered detectors only; used with 4-energy channel data to determine burst photon spectra. her_drm_X_YYYY.fits detector response matrix for 128-energy channel burst data for specified detector; used with 128-energy channel counts data to generate burst photon spectra. mer_drm_YYYY.fits detector response matrix for 16-energy channel burst data triggered detectors only; used with 16-energy channel data to generate burst photon spectra. cont_TJD_fits 8 BATSE detectors, 2.048s resolution/16 energy channels. discla_TJD.fits 8 BATSE detectors, 1.024 s resolution/4 energy channels. XXX_TJD1_TJD2_his.fits Occultation histories. XXX_TJD1_TJD2_nhis.fits Data for one or more BATSE detectors for available energy channels as source count rate (counts/sec) from which the background has been subtracted - used for light curves. XXX_TJD_lad_p11.fits Pulsar low level data. XXX_TJD1_TJD2_lad_olc Light curve file for a given pulsar.where YYYY = trigger number, XXXX = source name, TJD = Truncated Julian Day, X = detector number.
Notice that, because of the instrument configuration at the time of the event, the same files are not available for all triggers. Spectral (SD) data are prefixed with an 's' (e.g. 'sher').
Available data taken prior to the trigger may contain the beginning of the triggering event before it satisfied the triggering criteria. Background-type files can be used to remove background signal levels from the triggered period. The BFITS data files - containing burst and background spectral data as a function of time - and the detector response matrices (DRM) - modeling the instrument response to account for scattering and other effects - are extremely useful for gamma-ray burst analysis. Also, the BFITS and DRM files can be converted to PHA-II and RMF format for analysis with XSPEC using available FTOOLS. Other file types exist, notice, and advice on their use is obtainable at firstname.lastname@example.org.
Users must note that T90 and T50 are not available for those bursts which suffer from data gaps during the event; the integration procedure inherently fails in these cases. However, visual estimates of the burst duration are provided in the parameter Comments_Duration for those bursts with sufficient data coverage. Users may also find other pertinent comments concerning the calculated value of T90 and T50 therein, and it is highly recommended that this parameter be consulted before any distribution selected on T90 or T50 is used.
The BATSE on-board software tests for bursts by comparing the count rates on the eight large-area detectors to threshold levels for three separate time intervals: 64 ms, 256 ms, and 1024 ms. A burst trigger occurs if the count rate is above threshold in two or more detectors simultaneously. The thresholds are set by command to a specified number of standard deviations above background (nominally 5.5 sigma). Background rates are recomputed every 17 seconds. The thresholds exhibit a coarse quantization that results from truncating the square root of the 64-ms count rate. Since we require that rates be above the thresholds of at least two detectors, the trigger threshold is determined by the threshold of the second most brightly illuminated detector. When a burst trigger occurs, subsequent triggers are disabled during the accumulation period when the BATSE burst memories accumulate data. These data are then transmitted. During this readout period, the 64-ms threshold is revised to correspond to the maximum rate attained by the current burst, and triggering is disabled on the 256-ms and 1024-ms timescales. Bursts intense enough to trigger during this readout period are termed "over- writes". They are recognized in the database by the value of -999 in the threshold values for 256-ms and 1024-ms (called threshold_256 and threshold_1024 in this database).
Since a trigger can occur on any of the three timescales, there are often cases in which the maximum rate will be below threshold on one or two of the timescales. The value of V/Vmax can be determined for any burst by selecting the maximum of the three peak rates, raised to the -3/2 power. Many bursts have unknown counts or thresholds on one or more timescales. These are marked by a "-999" in the database. This can happen for one of the follow- ing reasons: (1) If the trigger occurs on the 64-ms timescale during the peak 256 ms rate, then the peak 256-ms rate is not found; (2) If the 64-ms peak rate never exceeds the 64-ms threshold, and it occurs before the trigger time, then the peak 64-ms rate is not found; (3) If the 256-ms peak rate never exceeds the 256-ms threshold, and it occurs before the trigger time, then the peak 256-ms rate is not found. Note that items 2 and 3 do not affect V/Vmax, since these peak rates do not exceed threshold; item 1 can, on rare occasions, lead to an overestimate of V/Vmax.
In analyzing these data, it is important to note that the trigger criteria, including the energy range, have been changed quite often since the end of the 3B catalog. This information is contained in the Trigger Criteria Table available at http://gammaray.msfc.nasa.gov/batse/grb/catalog/4b/4br_trigger_criteria.html
The BATSE trigger number. This is a running sequence number of BATSE triggers which include cosmic bursts, solar flares and other events. It is the primary means of identification for events in this catalog.
The BATSE burst name. Each burst has a unique catalog name. These names may have a prefix of either "4B" or "GRB". The "4B" prefix means that the burst is listed in BATSE 4B Catalog, while the "GRB" prefix means that the burst is listed in the BATSE Current Gamma-Ray Burst Catalog. The prefix is followed by the "yymmdd" (date) of the burst, where "yymmdd" is the two digit year, two digit month, and two digit day. An ending hyphen is added when this name is not unique, i.e., when there were two or more bursts on a particular day.
The Right Ascension of the object that triggered the BATSE instrument.
The Declination of the object that triggered the BATSE instrument.
Galactic longitude of the object that triggered the BATSE instrument.
Galactic latitude of the object that triggered the BATSE instrument.
The truncated Julian Date (TJD) of the trigger: TJD = JD - 2440000.5.
The burst trigger time. This parameter has been added by the HEASARC for the convenience of temporal searches and cross-correlations. The burst trigger time is the end of the interval (64, 256 or 1024 ms) in which the burst triggered the detector. The time system for the values is UT.
The burst trigger time, in decimal seconds of the day (UT) on which it occurred. The burst trigger time is the end of the interval (64, 256 or 1024 ms) in which the burst triggered the detector.
The radius in decimal degrees of the positional error box. The error in angular location is the radius of a circle having the same area as the 68% confidence ellipse defined by the formal covariance matrix from a chi^2 fit on the assumption of normal errors. The error is based solely on the Poisson uncertainty in the BATSE measurement of burst flux by each Large Area Detector. There is, in addition, an RMS systematic error of approximately 1.6 degrees. Adding 1.6 degrees in quadrature to the value of this parameter yields the BATSE team's estimate of the 68% confidence interval for the burst location error. The statistical error is believed to be Gaussian. The systematic error distribution has a more extended tail than a Gaussian.
The angle in decimal degrees of the geocenter, i.e., the angle between the burst and the nadir, as measured from the satellite.
The overwrite flag: this is Y (true) if this burst overwrote an earlier, weaker trigger, N (false) otherwise.
The overwritten flag: this is Y (true) if this burst was overwritten by a later, more intense trigger, N (false) otherwise.
The maximum counts in the second most brightly illuminated detector divided by the threshold count rate on the 64-ms timescale.
The trigger threshold on the 64-ms timescale. It is the number of counts in 64 ms required to trigger the second most brightly illuminated detector for this particular burst.
The peak flux on the 64-ms timescale in units of photons/cm^2/sec.
The one-sigma statistical error in the peak flux on the 64-ms timescale.
The time of the peak flux on the 64-ms timescale, in decimal seconds relative to the burst trigger time for the end of the interval in which the flux was calculated.
The maximum counts in the second most brightly illuminated detector divided by the threshold count rate on the 256-ms timescale.
The trigger threshold on the 256-ms timescale. It is the number of counts in 256 ms required to trigger the second most brightly illuminated detector for this particular burst.
The peak flux on the 256-ms timescale in units of photons/cm^2/sec.
The one-sigma statistical error in the peak flux on the 256-ms timescale.
The time of the peak flux on the 256-ms timescale, in decimal seconds relative to the burst trigger time for the end of the interval in which the flux was calculated.
The maximum counts in the second most brightly illuminated detector divided by the threshold count rate on the 1024-ms timescale.
The trigger threshold on the 1024-ms timescale. It is the number of counts in 1024 ms required to trigger the second most brightly illuminated detector for this particular burst.
The peak flux on the 1024-ms timescale in units of photons/cm^2/sec.
The one-sigma statistical error in the peak flux on the 1024-ms timescale.
The time of the peak flux on the 1024-ms timescale, in decimal seconds relative to the burst trigger time for the end of the interval in which the flux was calculated.
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.
The uncertainly in the T50 duration.
The start time of the T50 interval, relative to the trigger time (Time), in seconds.
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.
The uncertainty in the T90 duration.
The start time of the T90 interval, relative to the trigger time (Time), in seconds.
The fluence for Channel 1 (energy range 20-50 keV), in units of ergs/cm^2.
The error in the fluence for Channel 1.
The fluence for Channel 2 (energy range 50-100 keV), in units of ergs/cm^2.
The error in the fluence for Channel 2.
The fluence for Channel 3 (energy range 100-300 keV), in units of ergs/cm^2.
The error in the fluence for Channel 3.
The fluence for Channel 4 (energy range E > 300 keV), in units of ergs/cm^2. Since channel 4 is an integral channel, fluences given for this channel are quite sensitive to the assumed spectral form. Spectral analyses in this energy range should be performed with higher resolution data types.
The error in the fluence for Channel 4.
Comments on data quality for: not all gamma-ray bursts have such comments.
Comments on additional observations by other instruments: not all gamma-ray bursts have such comments.
General comments: not all gamma-ray bursts have such comments.
Comments on the gamma-ray burst coordinates: not all gamma-ray bursts have such comments.
Comments on the gamma-ray burst duration: not all gamma-ray bursts have such comments.