XMS - XMM-Newton Medium Sensitivity Survey (XMS) Source Catalog

Overview

X-ray sources at intermediate fluxes (a few x 10^-14 erg/cm²/s) with a sky density of ~ 100 deg² are responsible for a significant fraction of the cosmic X-ray background at various energies below 10 keV. The aim of this study is to provide an unbiased and quantitative description of the X-ray source population at these fluxes and in various X-ray energy bands. The XMM-Newton Medium sensitivity Survey (XMS) includes a total of 318 X-ray sources found among the serendipitous content of 25 XMM-Newton target fields. The XMS comprises four largely overlapping source samples selected at soft (0.5 - 2 keV), intermediate (0.5 - 4.5 keV), hard (2 - 10 keV) and ultra-hard (4.5 - 7.5 keV) bands, the first three of them being flux-limited.

This study reports on the optical identification of the XMS samples, complete to 85 - 95%. At the flux levels sampled by the XMS, the authors find that the X-ray sky is largely dominated by Active Galactic Nuclei. The fraction of stars in soft X-ray selected samples is below 10%, and only a few per cent for hard X-ray selected samples. They find that the fraction of optically obscured objects in the AGN population stays constant at around 15-20% for soft and intermediate band selected X-ray sources, over 2 decades of flux. The fraction of obscured objects amongst the AGN population is larger (~ 35 - 45%) in the hard or ultra-hard selected samples, and constant across a similarly wide flux range. The distribution in X-ray-to-optical flux ratio is a strong function of the selection band, with a larger fraction of sources with high values in hard selected samples. Sources with X-ray-to-optical flux ratios in excess of 10 are dominated by obscured AGN, but with a significant contribution from unobscured AGN.

Catalog Bibcode

2007A&A...476.1191B

References

The XMM-Newton serendipitous survey.
IV. Optical identification of the  XMM-Newton medium sensitivity survey (XMS).
    Barcons X., Carrera F.J., Ceballos M.T., Page M.J., Bussons-Gordo J.,
    Corral A., Ebrero J., Mateos S., Tedds J.A., Watson M.G., Baskill D.,
    Birkinshaw M., Boller T., Borisov N., Bremer M., Bromage G.E., Brunner H.,
    Caccianiga A., Crawford C.S., Cropper M.S., Della Ceca R., Derry P.,
    Fabian A.C., Guillout P., Hashimoto Y., Hasinger G., Hassall B.J.M.,
    Lamer G., Loaring N.S., Maccacaro T., Mason K.O., McMahon R.G., Mirioni L.,
    Mittaz J.P.D., Motch C., Negueruela I., Osborne J.P., Panessa F.,
    Perez-Fournon I., Pye J.P., Roberts T.P., Rosen S., Schartel N.,
    Schurch N., Schwope A., Severgnini P., Sharp R., Stewart G.C., Szokoly G.,
    Ullan A., Ward M.J., Warwick R.S., Wheatley P.J., Webb N.A., Worrall D.,
    Yuan W., Ziaeepour H.
   <Astron. Astrophys., 476, 1191-1203 (2007)>
   =2007A&A...476.1191B    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in March 2008 based on CDS catalog J/A+A/476/1191 files table2.dat and table5.dat.

Parameters

Name
The name for the X-ray source using the 'XMS' prefix for an XMM-Newton Medium Sensitivity X-ray source, and the truncated J2000.0 coordinates (JHHMMSS.s+DDMMSS), as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 1 arcsecond in the original table.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Error_Radius
The statistical error radius at the 90% confidence level in the position of the X-ray source.

Sample_Flags
This parameter contains flags [SHXU] which indicate the samples to which the source belongs, as follows:

             S = Soft X-ray band (0.5-2keV) sample
             H = Hard X-ray band (2-10keV) sample
             X = Intermediate X-ray band (0.5-4.5keV) sample
             U = Ultra-hard X-ray band (4.5-7.5keV) sample

SB_Flux
The X-ray source flux in the soft band (0.5 - 2 keV), in erg/s/cm².

SB_Flux_Error
The RMS uncertainty in the X-ray source flux in the soft band (0.5 - 2 keV), in erg/s/cm².

HB_Flux
The X-ray source flux in the hard band (2 - 10 keV), in erg/s/cm².

HB_Flux_Error
The RMS uncertainty in the X-ray source flux in the hard band (2 - 10 keV), in erg/s/cm².

IB_Flux
The X-ray source flux in the intermediate band (0.5 - 4.5 keV), in erg/s/cm².

IB_Flux_Error
The RMS uncertainty in the X-ray source flux in the intermediate band (0.5 - 4.5 keV), in erg/s/cm².

UB_Flux
The X-ray source flux in the ultra-hard band (4.5 - 7.5 keV), in erg/s/cm².

UB_Flux_Error
The RMS uncertainty in the X-ray source flux in the ultra-hard band (4.5 - 7.5 keV), in erg/s/cm².

Hardness_Ratio_2
The hardness ratio of the X-ray source, HR2= (H-S)/(H+S), where S and H are the exposure-time corrected count rates in the 0.5 - 2 keV and the 2 - 4.5 keV bands, respectively.

Hardness_Ratio_2_Error
The RMS uncertainty in the hardness ratio HR2.

RA_Optical_J2000
The J2000 Right Ascension of the optical counterpart to the X-ray source. Counterparts for the X-ray sources were searched for in the optical image lists. Candidate counterparts had to be either within the 5 statistical errors (at 90% confidence) of the X-ray position or within 5 arcseconds from the position of the X-ray source. This last criterion was used to accommodate any residual systematics in the astrometric calibration of the X-ray EPIC images.

Dec_Optical_J2000
The J2000 Declination of the optical counterpart to the X-ray source. Counterparts for the X-ray sources were searched for in the optical image lists. Candidate counterparts had to be either within the 5 statistical errors (at 90% confidence) of the X-ray position or within 5 arcseconds from the position of the X-ray source. This last criterion was used to accommodate any residual systematics in the astrometric calibration of the X-ray EPIC images.

Gmag_Limit
This parameter is set to '>' to indicate the corresponding magnitude for the optical counterpart to the X-ray source is a lower limit to the actual magnitude, i.e., it is an upper limit to the brightness.

Gmag
The SDSS g' magnitude of the optical counterpart to the X-ray source.

Rmag_Limit
This parameter is set to '>' to indicate the corresponding magnitude for the optical counterpart to the X-ray source is a lower limit to the actual magnitude, i.e., it is an upper limit to the brightness

Rmag
The SDSS r' magnitude of the optical counterpart to the X-ray source.

Imag_Limit
This parameter is set to '>' to indicate the corresponding magnitude for the optical counterpart to the X-ray source is a lower limit to the actual magnitude, i.e., it is an upper limit to the brightness

Imag
The SDSS i' magnitude of the optical counterpart to the X-ray source.

RJ_Mag
The Johnson R magnitude of the optical counterpart to the X-ray source.

Source_Flag
This flag parameter has the following values [YCE] containing information on the identification of the optical counterpart to the X-ray source:

        Y = source has been positively identified via optical spectroscopy
        C = there is a single clear optical candidate counterpart from in
            optical images
        E = there is no candidate counterpart down to our imaging sensitivity

Source_Type
The broad classification of the optical counterpart to the X-ray source. Based on the optical spectroscopy, the authors classify the counterparts to the XMS X-ray sources as in Barcons et al. (2002, A&A, 282, 522). Extragalactic sources exhibiting broad emission lines (velocity widths in excess of ~ 1500 km s^-1 are classified as BLAGN (Broad Line Active Galactic Nuclei); those exhibiting only narrow emission lines are termed NELG (Narrow Emission Line Galaxies); those with galaxy spectra without obvious emission lines are classified in principle as Absorption Line Galaxies (ALG). Of the latter, we distinguish two classes of exceptions: two of the sources with a galaxy spectrum without emission lines were previously catalogued as BL Lac objects and we classify them as such; if a qualitative inspection of the optical images show obvious evidence for a galaxy concentration we then classify the source as a cluster (Clus). Finally all X-ray sources with a stellar spectrum are labeled simply as 'Star'.

Redshift
The redshift of the optical counterpart to the XMS X-ray source, if it is extragalactic.

Class
The HEASARC Browse object classification, based on the value of the source_type parameter.

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:37:32 EDT