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This table lists all of the spectroscopy results of gamma-ray bursts observed by a subset of the 8 BATSE Large Area Detectors. BATSE consisted, in part, of an array of 8 sodium iodide Large Area Detectors (LADs) which covered the energy range from ~20 keV - 2 MeV. The LAD detectors were placed at each of the eight corners of the CGRO spacecraft with an outward orientation such that the entire sky not occulted by the Eartt was observed. The spectrum files ("scat" files) available as FITS-format data products associated with this catalog provide parameter values and goodness-of-fit measures for different types of spectral fits and models. These fits are performed using 14-channel data, usually 2-second resolution CONT data. There are currently two spectrum categories:
* Peak flux ('pflx') - a single spectrum over a 2.05-second time range at the
peak flux of the burst
* Fluence ('flnc') - a single spectrum over the entire burst duration
The quoted fluxes and fluences are for the 20 keV - 2 MeV energy range,
notice. The scat files have two extensions. The first extension gives
detector-specific information, including photon fluxes and fluences for each
detector, which are provided for each energy channel. The second extension
provides derived quantities such as flux, fluence and model parameters for
the joint fit of all included detectors. The scat files and their
energy-resolved quantities contained in these two extensions will be
available soon in the HEASARC data archive. Quantities derived from these
spectral fits are available in the present table, as described below and in
the Goldstein et al. (2013) reference paper.
The spectra are fit with a number of models, with the signal-to-noise ratio of the spectrum often determining whether a more complex model is statistically favored. The current set is:
* Power law ('plaw'),
* Comptonized (exponentially attenuated power law; 'comp')
* Band ('band')
* Smoothly broken power law ('sbpl')
* Log_10 Gaussian ('glog')
The full details of these models are presented in Section 4 of the reference
paper.
The type of spectrum and spectral model are coded into the parameter names (and the associated file names) using the acronyms given above. Thus for example, the parameters with names beginning with 'flnc_glog' contain the results from fits to the fluence spectra using Log10 Gaussian models. The corresponding spectrum file for the burst with trigger number 105 with the results from a fit to the fluence spectrum using a Log10 Gaussian model is named scat_0105_flnc_glog_v00.fit.
Please note that this table lists the raw results of each spectral fit to each GRB. In cases where the spectral fit failed, the values reported are those that initialized the spectral fit. If the uncertainty on the spectral parameters is reported as zero (no uncertainty), then the fit failed. In a few cases throughout this table, the uncertainties for certain spectral parameters may be reported as '9999.99' which indicates that the uncertainty on that parameter is completely unconstrained. An example of this is when the spectral data from a burst is fitted with a BAND function but is unable to constrain the high-energy index. In this case, the best fit centroid value of the high-energy index parameter is reported, and the '9999.99' value is reported for the uncertainty.
Bursts since the end of the 1B catalog (March 1992) occurred when the Compton Gamma-Ray Observatory (CGRO) tape recorders were experiencing numerous errors. Consequently, there are gaps in the data of many bursts that preclude valid measurement of peak flux, peak rate, fluence, or duration. Peak rates on the 1 second timescale from each detector are almost always available. These data (called MAXBC rates) can be used to determine burst location. Previous difficulties with this data type have been largely removed, and we now believe that the systematic errors for MAXBC-located bursts are the same as for bursts located with other data types. It is still true however, that the MAXBC-located bursts usually have larger statistical errors than would be the case if another data type were available. The parameter called comments_position in this database contains comments on MAXBC-located bursts. A number of CGRO and BATSE flight software changes have significantly reduced the problem of data gaps since March of 1993.
The authors also performed a deep-sampling of 180 objects (including the aforementioned 58 objects) combining data from the entire 9.1 year BATSE dataset. (One extra object, GRO J1735-27, has been added in this HEASARC table in addition to the 179 objects discussed in the reference paper). Source types considered were primarily accreting binaries, but a small number of representative active galaxies, X-ray-emitting stars, and supernova remnants were also included. The deep sample results include definite detections of 83 objects and possible detections of 36 additional objects. The definite detections spanned three classes of sources: accreting black hole and neutron star binaries, active galaxies and supernova remnants. Flux data for the deep sample are presented in four energy bands: 20-40, 40-70, 70-160, and 160-430 keV. The limiting average flux level (9.1 years) for the sample varies from 3.5 to 20 mCrab (5 sigma) between 20 and 430 keV, depending on systematic error, which in turn is primarily dependent on the sky location. To strengthen the credibility of detection of weaker sources (5-25 mCrab), the authors generated Earth occultation images, searched for periodic behavior using FFT and epoch folding methods, and critically evaluated the energy-dependent emission in the four flux bands.
For more information, visit the website https://heasarc.gsfc.nasa.gov/docs/cgro/batse/hilev/highlevel.html or refer to the Harmon et al. 2004 paper.
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.
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:
https://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:
https://heasarc.gsfc.nasa.gov/docs/cgro/batse/
Compton had four instruments that covered an unprecedented six decades of the electromagnetic spectrum, from 30 keV to 30 GeV. In order of increasing spectral energy coverage, these instruments were the Burst And Transient Source Experiment (BATSE), the Oriented Scintillation Spectrometer Experiment (OSSE), the Imaging Compton Telescope (CompTel), and the Energetic Gamma Ray Experiment Telescope (EGRET). BATSE viewed the full sky, as a transient monitor and is thus not included in this database table of pointed telescope observations. Also, EGRET and CompTel had wide fields of view, about 30 degrees, and, as such, viewed multiple targets per X-axis pointing. OSSE could be slewed (about one axis) independently from the spacecraft, so it typically viewed 2 targets per spacecraft Z-axis orientation, or "viewing period." Viewing periods were typically two weeks long.
This database table contains the CGRO observations for Cycles 1 through 9. The Cycle 1 observations for EGRET and COMPTEL were part of the All-Sky Survey with no defined targets.
https://heasarc.gsfc.nasa.gov/docs/cgro/
and from the article in Legacy No. 7 on the HEASARC CGRO Data Archive
https://heasarc.gsfc.nasa.gov/docs/journal/cgro7.html
Interactions in COMPTEL occur in a two stage process: First, a Compton
collision occurs in one of seven (low-Z) liquid scintillators and is usually
then completely absorbed in one of fourteen (high-Z) NaI(Tl) scintillators.
The unusual aspect of this detector is that the location of the gamma-ray on
the sky is given by an annulus and not a point. The correlation of many events
enables the localization of point sources or the creation of sky maps.
Time-of-flight measurements, pulse shape discrimination and anti-coincidence
shields are used to reject background events. COMPTEL has a wide field of view
(about 1 steradian, equivalent to a FWHM of about 40 degrees), an angular
resolution under optimal conditions of about 1 degree, and an energy resolution
that ranges from 5-10% at 1 MeV. During Phase 1 of the CGRO mission, COMPTEL
completed the first all-sky survey in the energy range of 0.75-30 MeV (in four
energy bands). In addition, COMPTEL can measure energy spectra of solar flares
or bright cosmic gamma-ray bursts between 0.1-10 MeV, and neutrons from solar
flares.
The authors applied a 2-dimensional maximum-likelihood detection method similar to that used to analyze the 3rd EGRET catalogue (3EG: Hartman et al. 1999, ApJS, 123, 79, available as the EGRET3 Catalog in Browse).
The revised EGRET catalog (EGR) lists 188 sources, 14 of which are marked as confused, in contrast to the 271 entries of the 3rd EGRET (3EG) catalog. The authors do not detect 107 sources discovered previously because additional structure is present in the interstellar background. The vast majority of them were unidentified and marked as possibly extended or confused in the 3EG catalog. In particular, the authors do not confirm most of the 3EG sources associated with the local clouds of the Gould Belt. Alternatively, they have found 30 new sources that have no 3EG counterpart. The new error circles for the confirmed 3EG sources largely overlap the previous ones, but several counterparts of particular interest discussed before, such as Sgr A*, radio galaxies, and several microquasars are now found outside the error circles. The authors cross-correlated the source positions with a large number of radio pulsars, pulsar wind nebulae, supernova remnants, OB associations, blazars and flat radiosources and they found a surprising large number of sources (87) at all latitudes that have no counterpart among the potential gamma-ray emitters.
Sources found within a radius of 1.5 PSF FWHM of a very bright source, and/or with very asymmetric TS map contours, are not included in the primary list of EGR sources but are included as EGRc sources herein. The EGRc sources represent significant excesses of photons above the background that may be due to extended sources, or structures not properly modeled in the interstellar emission, or artefacts due to incorrect PSF tails.
As noted above, there are 188 sources in this catalog: since there are multiple measurements for these sources corresponding to the various viewing periods, there are 1640 entries in the HEASARC's version of the Revised EGRET Catalog, corresponding to 1512 'observations' of the 174 primary gamma-ray sources plus 128 'observations' of the 14 confused sources. Thus, there are an average of about 9 entries for every gamma-ray source.
The 271 sources (E > 100 MeV) in the catalog include the single 1991 solar flare that was bright enough to detected as a source, the LMC, 5 pulsars, one probable radio galaxy detection (Cen A), and 66 high-confidence identifications of blazars (BL Lac objects, flat-spectrum radio quasars, or unidentified flat-spectrum radio sources). In addition, 27 lower-confidence potential blazar identifications are noted. Finally, the catalog contains 170 sources that are not yet firmly identified with known objects, although potential identifications have been suggested for a number of these.
As already noted, there are 271 distinct sources in this catalog: since there are multiple measurements for these sources corresponding to the various viewing periods, there are 5246 entries in the HEASARC's version of the 3rd EGRET Catalog corresponding to the same number of lines in Table 4 of the published version. Thus, there are an average of about 20 entries for every distinct source. Notice that 14 sources reported in the 2nd EGRET Catalog or its supplement do not appear in this 3rd EGRET Catalog: 2EG J0403+3357, 2EG J0426+6618, 2EGS J0500+5902, 2EGS J0552-1026, 2EG J1136-0414, 2EGS J1236-0416, 2EG J1239+0441, 2EG J1314+5151, 2EG J1430+5356, 2EG J1443-6040, 2EG J1631-2845, 2EG J1709-0350, 2EG J1815+2950, and 2EG J2027+1054 due to the fact that the re-analysis of the EGRET data has dropped their statistical significance from just above the catalog threshold to just below it; additional information on these sources is provided in Table 5 of the published version of the 3rd EGRET Catalog.
https://heasarc.gsfc.nasa.gov/docs/cgro/egret/egret_doc.html
Selection of GRBs for the GUSBAD Catalog requires a 5-sigma excess over the background in two of the BATSE detectors over the energy range 50-300 keV. The search covers the entire mission except when CGRO was over particular geographic regions or during one of 199,964 time windows when DISCLA data were missing or contaminated. The classification as GRB or non-GRB of the 6236 events that were produced by the software trigger was aided by correlating the times and positions of the events against the Current BATSE Burst Catalog. There are 589 GRBs in the GUSBAD Catalog that are not included in the Current BATSE Burst Catalog.
The GUSBAD catalog is uniform in the sense that the detection criterion is the same throughout and that the properties given in the catalog are available for every burst. The detection and the derivation of the properties listed in the catalog were carried out automatically, except for some rare instances. This makes the catalog especially suitable for statistical work and simulations, such as used in the evaluation of V/Vmax. The procedure used to detect and classify the bursts has been described in Schmidt (2004).