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BATSETRIGS: Help

BATSETRIGS - CGRO/BATSE Trigger Data


Overview

The BATSE Trigger data (each trigger is specified by a unique trigger number) are a set of triggered events that are classified as either a (solar) flare, (gamma-ray) burst, soft gamma-ray repeater (sgr), terrestrial gamma flash (tgf), or tagged with the name of a known source. Not all triggers pass the acceptance tests, so not all trigger numbers are present. For each trigger, there is an associated set of FITS data files that represent the raw data sources and some higher level data products. Spectral (SD) data are prefixed with an 's' (e.g. 'sher'). Not all data types are available for all triggers due to instrument mode differences.

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. Please refer to the Data_Products section for more details on the various file types.

A current description of the BATSE data holdings including the TRIGGER files is also available in the 1998 Legacy article, online at:

            http://heasarc.gsfc.nasa.gov/docs/journal/cgro7.html
General information about BATSE is available at the Compton Observatory Science Support Center (COSSC) web site at:
            http://cossc.gsfc.nasa.gov/docs/cgro/batse/

References

Fishman, G.J., et al. 1991, in Proc. The Compton Observatory Science
    Workshop (NASA CP-3137)
Wilson, R.B. et al. 1991, in Proc. The Compton Observatory Science Workshop
Harmon, B.A. et al. 1994, in 2nd Compton Symposium, AIP Conf. Proc. 304, 210
Briggs, M.S., et al. 1996, ApJ 459, 40
Meegan, C.A., et al. 1996, ApJ supplement, 106, 65
Finger, M.H., et al. 1997, in 4th Compton Symposium, AIP Conf. Proc 410, 57
Wilson, C.A. et al. 1998, to appear in ApJ, 499
Bildsten, L. et al. 1997, APJ Supplement, 113, 367

Provenance

This database table was created through a cooperative effort of the HEASARC and the Compton Observatory Science Support Center (COSSC). The table data were last updated in November 2003. The HEASARC added Galactic coordinates in August 2005.

Data Products

The following is a summary of the most useful BATSE data files and their contents:
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 grohelp@athena.gsfc.nasa.gov.


Parameters

_Trigger
The trigger number as a 5-character string, including leading zeroes.

ObsID
A unique tag created from the trigger number. Notice that this convention differs from that used for the other CGRO instruments for which the numerical part of the Obsid refers to the CGRO Viewing Period in which the data were obtained.

RA
Right ascension of the point of origin of the burst in the selected coordinate system.

Dec
Declination of the point of origin of the burst in the selected coordinate system.

LII
Galactic Longitude of the point of origin of the burst.

BII
Galactic Latitude of the point of origin of the burst.

Start_Time
The time at which the observation began. Note that this is not the start of the burst itself which is usually some time later.

Stop_Time
The time at which the observation ended. Note that this is not the end of the burst itself, which is usually some time earlier.

Trig_Type
The type of trigger: soft gamma repeater (SGR), Gamma Ray Burst (burst), solar flare (flare), terrestrial gamma flash (TGR), or the name of a source, e.g. CYGX-1 or GROJ1744-28.


Contact Person

Questions regarding the BATSETRIGS 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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