- ID:
- ivo://nasa.heasarc/saxgrbmgrb
- Title:
- BeppoSAX/GRBM Gamma-Ray Burst Catalog
- Short Name:
- SAXGRBMGRB
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This is the catalog of gamma-ray bursts (GRBs) detected with the Gamma Ray Burst Monitor (GRBM) aboard the BeppoSAX satellite. It includes 1082 GRBs with 40 - 700 keV fluences in the range from 1.3 x 10<sup>-7</sup> to 4.5 x 10<sup>-4</sup> erg/cm<sup>2</sup>, and 40 - 700 keV peak fluxes from 3.7x10<sup>-8</sup> to 7.0 x 10<sup>-5</sup> erg/cm<sup>2</sup>/s. Some relevant parameters of each GRB are reported in the catalog. This table was created by the HEASARC in January 2010 based on the CDS catalog J/ApJS/180/192, file table2.dat. This is a service provided by NASA HEASARC .
« Previous |
1 - 10 of 15
|
Next »
Number of results to display per page
Search Results
- ID:
- ivo://nasa.heasarc/grbcat
- Title:
- Catalog of Gamma-Ray Bursts
- Short Name:
- GRBCAT
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This GRBs Catalog (GRBCAT) records high level information of the GRBs detected since their discovery in 1967. The catalog has been created using publications that report lists of GRB detections. These are mostly papers already published in refereed journals, unpublished papers, and PhD thesis presenting lists of GRBs. GRBCAT includes also compilation of bursts that were already present in the HEASARC database system. The catalog is organized with a main table reporting general information for each GRB and additional tables linked to the main table where specific information for the flux and the region of detection are reported. Afterglow measurements are also recorded in a separate table for all bursts detected after May 11 1996. The main table for each GRB contains an entry for each satellite that reports a detection with either a flux and/or position measurement. Therefore for a given GRB there are multiple records if the GRB was detected by more than one satellite. The associated flux table contains an entry for each flux and fluence values reported in literature for a given energy band. The positional information is reported via different tables each dedicated to a specific region of detection. The region descriptions are the following : circle, annulus, box, dual, annulus intersect, irregular, and intersect. The associated afterglow table contains position, intensity and redshift measurements taken after the discovery of the GRB. There are several records associated to a given GRB/afterglow since several observatories collected data on that position. The main table and the associated tables are updated when a new GRB and/or afterglow measurements are reported. This table was ingested by the HEASARC in June 2008 based on electronic versions obtained from the author(s), who compiled the catalog in 2005. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/batse4b
- Title:
- CGRO/BATSE 4B Catalog
- Short Name:
- BATSE4B
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table comprises the 4th BATSE Gamma-Ray Burst Catalog, hereafter referred to as 4B. It specifies the locations and times for 1637 triggered gamma-ray bursts observed from 19 April, 1991 until 29 August, 1996. It therefore includes the data from the 3B catalog. The only revisions from the 3B catalog are improved locations for the trigger #s 741, 2311, and 3155. 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. This database table was created by the HEASARC in March 1999, based on data supplied by the CGRO Science Support Center. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/bat5bgrbsp
- Title:
- CGRO/BATSE 5B Gamma-Ray Burst Spectral Catalog
- Short Name:
- BAT5BGRBSP
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The CGRO/BATSE 5B Gamma-Ray Burst Spectral Catalog contains the results of systematic spectral analyses of gamma-ray bursts (GRBs) detected with the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma-Ray Observatory (CGRO) during its entire nine years of operation. This catalog contains two types of spectra extracted from 2,145 GRBs, and fitted with five different spectral models resulting in a compendium of over 19,000 spectra. The models were selected based on their empirical importance to the spectral shape of many GRBs, and the analysis performed was devised to be as thorough and objective as possible. In their paper, the authors describe in detail their procedures and criteria for the analyses, and present the bulk results in the form of parameter distributions. This catalog should be considered an official product from the BATSE Science Team, and the data files containing the complete results are soon to be available from the HEASARC. 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: <pre> * 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 </pre> 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: <pre> * Power law ('plaw'), * Comptonized (exponentially attenuated power law; 'comp') * Band ('band') * Smoothly broken power law ('sbpl') * Log_10 Gaussian ('glog') </pre> 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 Log<sub>10</sub> 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 Log<sub>10</sub> 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. This table was created by the HEASARC in November 2013 based on electronic versions of Tables 6 through 10, inclusive, from the reference paper which were obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/batsegrbsp
- Title:
- CGRO/BATSE Complete Spectral Catalog of Bright GRBs
- Short Name:
- BATSE/Spec
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The CGRO/BATSE Complete Spectral Catalog of Bright Gamma-Ray Bursts (GRBs) contains the results of a systematic spectral analysis of 350 bright GRBs observed with the Burst and Transient Source Experiment (BATSE; spectral range ~ 30 keV - 2 MeV) with high temporal and spectral resolution. The sample was selected from the complete set of 2704 BATSE GRBs based on their energy fluence or peak photon flux values in order to assure good statistics, and included 17 short GRBs. To obtain well-constrained spectral parameters, several photon models were used to fit each spectrum. Spectral parameters resulting from the fits using different models were compared, and the spectral parameters that best represent each spectrum were statistically determined, taking into account the parametrization differences among the models. A thorough analysis was performed on 350 time-integrated and 8459 time-resolved burst spectra, and the effects of integration times in determining the spectral parameters were explored. Using the results, correlations among spectral parameters and their evolution pattern within each burst were studied. The resulting spectral catalog provides reliable constraints on particle acceleration and emission mechanisms in GRBs, and is the most comprehensive study of spectral properties of GRB prompt emission to date. The files containing the details of the spectral model fits to the GRBs are also available as data products associated with this Browse table. This table was created in May 2006 based on the electronic versions of Tables 1 and 9 from the published paper which were supplied by the author. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/batsegrb
- Title:
- CGRO/BATSE Gamma-Ray Burst Catalog
- Short Name:
- BATSEGRB
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This database table comprises the gamma-ray bursts detected by the BATSE instrument on the Compton Gamma-Ray Observatory (CGRO). It includes the gamma-ray bursts from the BATSE 4B Catalog (triggers 105 through 5586, observed between April 19, 1991, and August 29, 1996) as well as a large number of triggered bursts since the publication of the BATSE 4B 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 data files used to construct this database table are obtained from the following pages on the BATSE GRB Team website: <pre> BATSE Current Gamma-Ray Burst Catalog: <a href="http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/">http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/</a> Some flux and fluence data and all the comments are from the BATSE 4B Catalog: <a href="http://gammaray.msfc.nasa.gov/batse/grb/catalog/4b/">http://gammaray.msfc.nasa.gov/batse/grb/catalog/4b/</a> </pre> <p> 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 <a href="http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/">http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/</a> are changed. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/batsetrigs
- Title:
- CGRO/BATSE Trigger Data
- Short Name:
- BATSETRIGS
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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: <pre> <a href="https://heasarc.gsfc.nasa.gov/docs/journal/cgro7.html">https://heasarc.gsfc.nasa.gov/docs/journal/cgro7.html</a> </pre> General information about BATSE is available at the Compton Observatory Science Support Center (COSSC) web site at: <pre> <a href="https://heasarc.gsfc.nasa.gov/docs/cgro/batse/">https://heasarc.gsfc.nasa.gov/docs/cgro/batse/</a> </pre> 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. The "_trigger" field was renamed to "trigger_id" in September, 2020. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermigbrst
- Title:
- Fermi GBM Burst Catalog
- Short Name:
- FERMIGBRST
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- When referencing results from this online catalog, please cite <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ab7a18">von Kienlin, A. et al. 2020</a>, <a href="http://iopscience.iop.org/0067-0049/211/1/12/">Gruber, D. et al. 2014</a>, <a href="http://iopscience.iop.org/0067-0049/211/1/13/">von Kienlin, A. et al. 2014</a>, and <a href="http://iopscience.iop.org/article/10.3847/0067-0049/223/2/28/">Bhat, P. et al. 2016</a>. This table lists all of the triggers observed by a subset of the 14 GBM detectors (12 NaI and 2 BGO) which have been classified as gamma-ray bursts (GRBs). Note that there are two Browse catalogs resulting from GBM triggers. All GBM triggers are entered in the <a href="/W3Browse/fermi/fermigtrig.html">Fermi GBM Trigger Catalog</a>, while only those triggers classified as bursts are entered in the Burst Catalog. Thus, a burst will be found in both the Trigger and Burst Catalogs. The Burst Catalog analysis requires human intervention; therefore, GRBs will be entered in the Trigger Catalog before the Burst Catalog. The latency requirements are 1 day for triggers and 3 days for bursts. There are four fewer bursts in the online catalog than in the Gruber et al. 2014 paper. The four missing events (081007224, 091013989, 091022752, and 091208623) have not been classified with certainty as GRBs and are not included in the general GRB catalog. This classification may be revised at a later stage. The GBM consists of an array of 12 sodium iodide (NaI) detectors which cover the lower end of the energy range up to 1 MeV. The GBM triggers off of the rates in the NaI detectors, with some Terrestrial Gamma-ray Flash (TGF)-specific algorithms using the bismuth germanate (BGO) detectors, sensitive to higher energies, up to 40 MeV. The NaI detectors are placed around the Fermi spacecraft with different orientations to provide the required sensitivity and FOV. The cosine-like angular response of the thin NaI detectors is used to localize burst sources by comparing rates from detectors with different viewing angles. The two BGO detectors are placed on opposite sides of the spacecraft so that all sky positions are visible to at least one BGO detector. The signals from all 14 GBM detectors are collected by a central Data Processing Unit (DPU). This unit digitizes and time-tags the detectors' pulse height signals, packages the resulting data into several different types for transmission to the ground (via the Fermi spacecraft), and performs various data processing tasks such as autonomous burst triggering. The GRB science products are transmitted to the FSSC in two types of files. The first file, called the "bcat" file, provides basic burst parameters such as duration, peak flux and fluence, calculated from 8-channel data using a spectral model which has a power-law in energy that falls exponentially above an energy EPeak, known as the Comptonized model. The crude 8-channel binning and the simple spectral model allow data fits in batch mode over numerous time bins in an efficient and robust fashion, including intervals with little or no flux, yielding both values for the burst duration, and deconvolved lightcurves for the detectors included in the fit. The bcat file includes two extensions. The first, containing detailed information about energy channels and detectors used in the calculations, is detector-specific, and includes the time history of the deconvolved flux over the time intervals of the burst. The second shows the evolution of the spectral parameters obtained in a joint fit of the included detectors for the model used, usually the Comptonized model described above. The bcat files and their time-varying quantities contained in these two extensions are available at the HEASARC FTP site. Quantities derived from these batch fits are given in the bcat primary header and presented in the Browse table, as described below. The main purpose of the analysis contained in the bcat file is to produce a measure of the duration of the burst after deconvolving the instrument response. The duration quantities are: <pre> * 't50' - the time taken to accumulate 50% of the burst fluence starting at the 25% fluence level. * 't90' - the time taken to accumulate 90% of the burst fluence starting at the 5% fluence level. </pre> By-products of this analysis include fluxes on various timescales and fluences, both obtained using the simple Comptonized model described above. These quantities are detailed in the Browse table using the following prefixes: <pre> * 'flux' - the peak flux over 3 different timescales obtained in the batch mode fit used to calculate t50/t90. * 'fluence' - the total fluence accumulated in the t50/t90 calculation. </pre> The fluxes and fluences derived from the 8-channel data for these bcat files should be considered less reliable than those in the spectral analysis files described below. Analysis methods used in obtaining these quantities are detailed in the first GBM GRB Catalog (Paciesas et al. 2011). Updates of bcat files will be sent (with new version numbers) as these parameters are refined. This "bcat" file is produced for triggers that are classified as GRBs (with exceptions as described below), and supplements the initial data in the trigger or "tcat" file that is produced for all triggers. The second type of file (the spectrum or "scat" file) provides parameter values and goodness-of-fit measures for different types of spectral fits and models. These fits are performed using 128-channel data, either CSPEC or, for short bursts, TTE data. The type and model are coded into the file name. There are currently two spectrum categories: <pre> * Peak flux ('pflx') - a single spectrum over the time range of the peak flux of the burst * Fluence ('flnc') - a single spectrum over the entire burst duration selected by the duty scientist. </pre> Like the bcat files, 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 are available in the Fermi data archive at the HEASARC. Quantities derived from these spectral fits are available in the Browse table, as described below and in Goldstein et al. (2011). 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: <pre> * Power law ('plaw'), * Comptonized (exponentially attenuated power law; 'comp') * Band ('band') * Smoothly broken power law ('sbpl') </pre> <b>Warnings</b> The bcat and scat files result from two completely independent analyses, and consequently, it is possible that the same quantities might show differences. Indeed, 1) the fluxes and fluences in the "scat" files should be considered more reliable than those in the "bcat" files, with the official fluxes and fluences being those yielded by the statistically favored model ("Best_Fitting_Model" in the Browse table) and with the full energy resolution of the instrument; 2) in both the bcat and scat analyses, the set of detectors used for the fits ("Scat_Detector_Mask" in the Browse table) may not be the same as the set of detectors that triggered GBM ("Bcat_Detector_Mask" in the Browse table); 3) background definitions are different for the bcat and scat analysis (see References below). Finally, for weak events, it is not always possible to perform duration or spectral analyses, and some bursts occur too close in time to South Atlantic Anomaly entries or exits by Fermi with resultant data truncations that prevent background determinations for the duration analysis. There is not an exact one-to-one correspondence between those events for which the duration analysis fails and those which are too weak to have a useful spectral characterization. This means that in the HEASARC Browse table there are a handful of GRBs which have duration parameters but not spectral fit parameters, and vice versa. In these cases, blank entries in the table indicate missing values where an analysis was not possible. Values of 0.0 for the uncertainties on spectral parameters indicate those parameters have been fixed in the fit from which other parameters or quantities in the table were derived. Missing values for model fit parameters indicate that the fit failed to converge for this model. This is true mostly for the more complicated models (SBPL or BAND) when the fits fail to converge for weaker bursts. Bad spectral fits can often result in unphysical flux and fluence values with undefined errors. We include these bad fits but leave the error fields blank when they contain undefined values. The selection criteria used in the first catalog (Goldstein et al. 2011) for the determination of the best-fit spectral model are different from those in the second catalog (Gruber et al. 2014). The results using the two methods on the sample included in Goldstein et al. (2011) are compared in Gruber et al. (2014). The old catalog files can be retrieved using the HEASARC ftp archive tree, under "previous" directories. The values returned by Browse always come from the "current" directories. The chi-squared statistic was not used in the 2nd catalog, either for parameter optimization or model comparison. The chi-squared values are missing for a few GRBs. This is believed to be because of a known software issue and should not be considered indicative of a bad fit. The variable "scatalog" included in the Browse tables and in the FITS files indicates which catalog a file belongs to, with 2 being the current catalog, and 1 (or absent) the first catalog (preliminary values may appear with value 0). The information in this table is provided by the Fermi Gamma-ray Burst Monitor Instrument Operations Center (GIOC) and the Fermi Science Support Center (FSSC). The values come from burst and spectral catalog entry FITS files provided by the GIOC to the FSSC. These FITS files may contain additional data and are available for download. This table is updated automatically within a day or so of new data files being processed and made available. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilgrb
- Title:
- Fermi LAT Second Gamma-Ray Burst Catalog
- Short Name:
- FERMILGRB
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The LAT routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present the second catalog of LAT-detected GRBs. Initially, the second catalog covered the only the first 10 years of operations, from 2008 August 4 to 2018 August 4. The table given here has been supplemented to add later GRBs that were analyzed using the same procedure as the original catalog. It will be updated periodically with new GRBs. This database table was last updated by the HEASARC in April 2022 using electronic data obtained from the Fermi Science Support Center (FSSC). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/gusbad
- Title:
- GRBs Uniformly Selected from BATSE Archival Data (Version 2.1)
- Short Name:
- BATSE/GUSBAD
- Date:
- 10 May 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The GUSBAD (Gamma-ray bursts Uniformly Selected from BATSE Archival Data) Catalog is based on BATSE DISCLA data at a time resolution of 1.024 seconds for the full 9.1 years of the Compton Gamma-Ray Observatory (CGRO) mission from April 19, 1991 until May 26, 2000 (corresponding to Truncated Julian Dates from 8365 to 11690). This catalog lists over 2200 gamma-ray bursts (GRBs). 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). This database table was last updated by the HEASARC in April 2005 using the file GUSBADcat.dat containing version 2.1 of the catalog, which was obtained from the catalog author's web site at <a href="http://www.astro.caltech.edu/~mxs/grb/GUSBAD/">http://www.astro.caltech.edu/~mxs/grb/GUSBAD/</a> <p> Comments or questions about the contents of the GUSBAD Catalog are welcomed by the author who can be contacted at mxs@astro.caltech.edu. This is a service provided by NASA HEASARC .
