RASSBSCPGC - ROSAT All-Sky Survey Bright Source Catalog/Catalog of Principal Galaxies Matches

Overview

In a correlation study of the ROSAT All-Sky Survey Bright Source Catalog (RASS-BSC, CDS Cat. <XI/10>, the HEASARC table RASSBSC) with the Catalogue of Principal Galaxies (PGC, CDS Cat. <VII/119>, the HEASARC table PGC2003), 904 X-ray sources were found that possess possible extragalactic counterparts within a search radius of 100 arcseconds. A visual screening process was applied to classify the reliability of the correlations. 547 correlations have been quoted as reliable identifications. From these, 349 sources are known to be active galaxies. Although for the other sources no hints for activity were found in the literature, 69% of those for which we have distances show X-ray luminosities exceeding those of normal galaxies, a clear sign that these galaxies also own hitherto unreported X-ray active components. Some objects are located inside or in the direction of a known group or cluster of galaxies. Their X-ray flux may therefore be in part affected by hot gas emission. In the paper, luminosity and log N-log S distributions are used to characterize different subsamples. Nuclei that are both optically and X-ray active are found predominantly in spirals. Two special source samples are defined, one with candidates for X-ray emission from hitherto unknown groups or clusters of galaxies, and one with high X-ray luminosity sources, that are likely candidates to possess hitherto unreported active galactic nuclei. Besides a compilation of X-ray and optical parameters, X-ray overlays on optical images for all the objects are also supplied as part of this work.

This table contains 1124 optical galaxy entries for the 904 relevant X-ray candidates/counterparts from the RASS. Besides a compilation of X-ray and optical parameters for each source, the results of an identification screening are also given. The 904 optical images with X-ray overlay contours (xID_nnn.ps.gz) used in the screening process are added for each user's own judgement of the reliability of the associations.

Catalog Bibcode

2001A&A...378...30Z

References

Galaxy identifications in the ROSAT All-Sky Survey.
       Zimmermann H.-U., Boller T., Doebereiner S., Pietsch W.
      <Astron. Astrophys. 378, 30 (2001)>
      =2001A&A...378...30Z

Provenance

This table was created by the HEASARC in March 2012 based on CDS catalog J/A+A/378/30 file table1.dat, the list of PGC galaxies identified as possible counterparts to RASS Bright Source Catalog X-ray sources.

HEASARC Implementation

The HEASARC has removed the parameter which coded the reference sources for the optical parameters which was present in the original CDS table since the tabulated values disagreed with the coding scheme given in the CDS documentation.

Parameters

Source_Number
A unique identification number (1 - 1124) for each PGC galaxy which is a potential counterpart to a RASS-BSC X-ray source.

XID_Number
A unique identification number (1 - 904) for each RASS-BSC X-ray source, also used to identify the appropriate overlay image.

PGC_Candidate_Number
This number (1 - 10) identifies the optical galaxy candidate for a specific X-ray source. Most X-ray sources have only 1 PGC galaxy correlation, but some have multiple (up to 10) associations.

RASS_Name
The 1RXS identifier for the RASS-BSC X-ray source, viz. '1RXS JHHMMSS.s+DDMMSS'.

RA
The Right Ascension of the RASS-BSC X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the RASS-BSC X-ray source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the RASS-BSC X-ray source.

BII
The Galactic Latitude RASS-BSC X-ray source.

Exposure
The exposure time of the RASS-BSC X-ray source, in seconds.

Error_Radius
The uncertainty in the position of the RASS-BSC X-ray source, in arcseconds.

Count_Rate
The RASS-BSC X-ray source count rate in the 0.1 - 2.4 keV band, in ct s^-1.

Count_Rate_Error
The uncertainty in the RASS-BSC X-ray source count rate in the 0.1 - 2.4 keV band, in ct s^-1.

Detect_Likelihood
The likelihood L_D of the RASS-BSC X-ray source detection, where e^-L_D is the probability that the source is spurious.

Counts
The total counts from the RASS-BSC X-ray source in the 0.1 - 2.4 keV band.

Extended_Likelihood
The likelihood L_E of the RASS-BSC X-ray source being extended, where e^-L_E is the probability that the source is extended (the authors caution that this should be interpreted with care).

Angular_Extent
The angular extent of the RASS-BSC X-ray source, in arcseconds.

Name
The name of the optical galaxy counterpart candidate.

PGC_RA
The Right Ascension of the optical galaxy counterpart candidate in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table.

PGC_Dec
The Declination of the optical galaxy counterpart candidate in the selected equinox. This was given in J2000.0 equatorial coordinates to a (true) precision of 0.1 arcseconds in the original table.

Bmag
The B magnitude of the optical galaxy counterpart candidate, from NED.

Opt_Error_Radius
The uncertainty in the optical position, in arcseconds.

Object_Type
The galaxy type of the optical galaxy counterpart candidate using the Simbad/NED classification.

Detailed_Type
The detailed galaxy type of the optical galaxy counterpart candidate.

Activity_Type
The activity type of the optical galaxy counterpart candidate, if any.

Radial_Velocity
The heliocentric recession velocity of the optical galaxy counterpart candidate, in km s^-1.

Cluster_Flag
This flag parameter indicates whether the galaxy is apparently single (if 0), a member of a galaxy pair (if 1), a member of a galaxy group (if 2), or a member of a galaxy cluster or near to the line-of-sight projection towards a cluster of galaxies (if 3).

NH_Gal
The Galactic Hydrogen column density in the direction of the source, in H atoms cm^-2.

RASS_PGC_Offset
The angular distance between the RASS-BSC X-ray source and the optical galaxy counterpart candidate, in arcseconds.

Log_Flux
The logarithm of the X-ray flux of the RASS-BSC source in the 0.1-2.4 keV X-ray band, in erg s^-1 cm^-2.

Log_Lx
The logarithm of the X-ray luminosity of the RASS-BSC source in the 0.1-2.4 keV X-ray band, in erg s^-1, assuming a Hubble constant H₀ value of 70 km s^-1 Mpc^-1.

Corr_Reliability
The reliability of the correlation of the X-ray source and the optical counterpart.

Comments
Comments on the identification and/or source properties, where 'cl?' means taht the source belongs to the "suspected cluster sample".

Class
The HEASARC Browse object classification, based on the activity_type value only.

Contact Person

Questions regarding the RASSBSCPGC database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:33:21 EDT