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RIXOS - ROSAT International X-Ray/Optical Survey Source Catalog

HEASARC
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Overview

The ROSAT International X-Ray/Optical Survey (RIXOS) is a medium-sensitivity survey and optical identification program for X-ray sources which were discovered in ROSAT high Galactic latitude fields (|b| > 28 degrees) and observed with the Position Sensitive Proportional Counter (PSPC) detector. The survey made use of the central 17 arcmin of each ROSAT field. A flux limit of 3 x 10-14 erg/s/cm2 (0.5-2.0 keV) was adopted for this survey, and a minimum exposure time of 8000 seconds was required for qualifying ROSAT observations. X-ray sources in the survey are therefore substantially above the detection threshold of each field used, and many contain enough counts to allow the X-ray spectral slope to be estimated. Spectroscopic observations of potential counterparts were obtained of all sources down to the survey limit in 64 fields, totaling a sky area of 15.77 square degrees. Positive optical identifications are made for 94% of the 296 sources thus examined. A further 18 fields (4.44 sq deg), containing 105 sources above the 3 x 10-14 erg/s/cm2 survey limit, are completely optically identified to a higher flux of 8 x 10-14 erg/s/cm2 (0.5-2.0 keV). Optical spectroscopic data are supplemented by deep CCD imaging of many sources to reveal the morphology of the optical counterparts, and objects too faint to register on Sky Survey plates. The faintest optical counterparts have R ~ 22.

This table contains the catalog of the RIXOS sources and their optical identifications.


Catalog Bibcode

2000MNRAS.311..456M

References

The ROSAT International X-ray/Optical Survey (RIXOS): source catalogue
    Mason K.O., Carrera F.J., Hasinger G., Andernach H.,
    Aragon-Salamanca A., Barcons X., Bower R., Brandt W.N.,
    Branduardi-Raymont G., Burgos-Martin J., Cabrera-Guerra F., Carballo R.,
    Castander F., Ellis R.S., Gonzalez-Serrano J.I., Martinez-Gonzalez E.,
    Martin-Mirones J.M., McMahon R.G., Mittaz J.P.D., Nicholson K.L.,
    Page M.J., Perez-Fournon I., Puchnarewicz E.M., Romero-Colmenero E.,
    Schwope A.D., Vila B., Watson M.G., Wonnacott D.
    <Mon. Not. R. Astron. Soc. 311, 456 (2000)>
    =2000MNRAS.311..456M      (SIMBAD/NED BibCode)

Provenance

This table was originally ingested by the HEASARC in June 2005 based on CDS table J/MNRAS/311/456/rixos.dat. It was updated in November 2013 shortly after the CDS released an update with the previously inadvertently omitted source RX J111809.9+212554 (RIXOS 123_84) included.

Parameters

Name
The ROSAT X-ray source designation, derived from the J2000 equatorial coordinates of the X-ray centroid.

Opt_ID
Most of the RIXOS X-ray sources have information on only a single optical counterpart, but there are 8 cases where there are two optical counterparts listed. The HEASARC has created this parameter to flag the second counterparts in these cases with a value of 2, compared to the default value of 1.

Error_Radius
The X-ray 90% confidence positional radius in arcseconds.

RA
The Right Ascension of the optical counterpart, if it is a single object, or of the X-ray centroid, if it is a cluster or an unidentified source, in the selected equinox. This was given in J2000 coordinates and to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the optical counterpart, if it is a single object, or of the X-ray centroid, if it is a cluster or an unidentified source, in the selected equinox. This was given in J2000 coordinates and to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the RIXOS object.

BII
The Galactic Latitude of the RIXOS object.

Flux
The X-ray flux (0.5-2.0 keV) of the ROSAT source, in erg/s/cm2, derived from the measured count rate assuming a spectral slope of alpha = -1. This is the flux which has been used to define membership in the catalog.

Flux_Unabs
The X-ray flux (0.5-2.0 keV) of the ROSAT source, in erg/s/cm2, derived from the best-fitting spectral slope and (with the exception of stellar IDs) after correcting for Galactic absorption.

Count_Rate
The X-ray count rate, in ct/s.

Count_Rate_Error
The RMS uncertainty in the X-ray count rate, in ct/s.

Ml_Counts
The total X-ray counts based on maximum likelihood fits.

Xray_Spect_Index
The X-ray spectral index alpha_x defined such that F_x ~ energy^alpha_x and derived by fitting 3-color X-ray data assuming Galactic absorption (except for stellar IDs). See Mittaz et al. (1999, MNRAS, 308, 233) for more details.

Xray_Spect_Index_Error
The RMS uncertainty in the X-ray spectral index.

App_Mag_Type
A flag parameter which indicates the type of optical magnitude, as follows:

      C - from other catalogs (see Table 3 of the published paper);
      E - from APM measurements of POSS-E plates;
      O - from APM measurements of POSS-O plates;
      R - from R-band CCD images;
      V - from V-band CCD images;
      S - slit magnitudes derived by folding the spectrum through the
           R-band response. The typical accuracy of the slit magnitudes is
           about 30% (see Puchnarewicz et al., 1996MNRAS.281.1243P).
  

App_Mag
The magnitude of the Optical Counterpart (or the brightest galaxy, for clusters).

Opt_Spect_Index
The slope alpha_o of the optical continuum. Uncertainties in the slope are about 50% and are dominated by systematic effects (see Puchnarewicz et al., 1996MNRAS.281.1243P).

ID_Flag
A flag parameter which is set to ':' to indicate uncertainty in the identification.

Broad_Class
The broad category of the optical identification in one of 5 categories: 'Star', 'AGN', 'ELG' (for emission-line galaxy), 'Clus' (for cluster of galaxies), or 'Gal' (for galaxy). The number in parentheses following the 'Clus' category indicates the number of cluster galaxies whose redshifts have been measured.

Source_Type
The optical classification subtype, for stars being the spectral type, and for AGN being the specific AGN type.

Redshift_Flag
A flag parameter which is set to ':' to indicate uncertainty in the quoted redshift.

Redshift
The redshift (for extragalactic counterparts).

Emission_Lines
The emission lines observed in AGN and ELG identifications. The line used in the calculation of the FWHM is indicated by the trailing asterisk.

Emission_FWHM
The full-width half-maximum (FWHM) of the annotated emission line, in units of km/s, rounded down to the nearest integral value of 103 km/s. Preference is given to the H-beta or MgII lines when they are available and well defined. Otherwise, the best defined permitted line in the spectrum is used. More complete details of emission line measurements are given in Puchnarewicz et al. (1997MNRAS.291..177P).

Emission_FWHM_Flag
A flag parameter which is set to ':' to indicate uncertainty in the quoted value for the emission line FWHM.

Note_Flag
Non-blank values for this parameter signify as follows: 'C', that there is a catalogue cross-reference in table 3 of the published paper, 'N' that there is an additional note in section 3.2 of the published paper, and 'I' that there is a CCD image of the field in Fig. 4 of the paper.

Alt_Name
The RIXOS source designation, in the form 'RIXOS FFF-NNN', where FFF is the Field ID and NNN is the source ID within the field.

Class
The HEASARC Browse object classification, based on the value of the source_type parameter, if available, else on the value of the broad_class parameter.


Contact Person

Questions regarding the RIXOS database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 16-Dec-2013