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CFHTLSGXMM - XMM-Newton CFHTLS W1 Field Galaxy Groups Catalog

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Overview

This table contains a catalog of 128 X-ray galaxy groups, covering a redshift (z) range 0.04 < z <1.23, selected in the ~ 3 deg2 part of the CFHTLS W1 field overlapping XMM-Newton observations performed under the XMM-LSS project. The authors carry out a statistical study of the redshift evolution out to redshift 1 of the magnitude gap between the first and the second brightest cluster galaxies of a well defined mass-selected group sample. They find that the slope of the relation between the fraction of groups and the magnitude gap steepens with redshift, indicating a larger fraction of fossil groups at lower redshifts. They also find that 22.2% +/- 6% of their groups at z <= 0.6 are fossil groups.

The authors compare their results with the predictions of three semi-analytic models based on the Millennium simulation. The intercept of the relation between the magnitude of the brightest galaxy and the value of magnitude gap becomes brighter with increasing redshift. This trend is steeper than the model predictions which the authors attribute to the younger stellar age of the observed brightest cluster galaxies. This trend argues in favor of stronger evolution of the feedback from active galactic nuclei at z < 1 compared to the models. The slope of the relation between the magnitude of the brightest cluster galaxy and the value of the gap does not evolve with redshift and is well reproduced by the models, indicating that the tidal galaxy stripping, put forward as an explanation of the occurrence of the magnitude gap, is both a dominant mechanism and sufficiently well modeled.

In this study, the authors analyzed the XMM-Newton observations of the CFHTLS wide (W1) field as a part of the XMM-LSS survey (Pierre et al., 2007, MNRAS, 382, 279). The details of the observations and the data reduction are presented in Bielby et al. (2010, A&A, 523, A66). The authors concentrate on the low-z counterparts of the X-ray sources and use all XMM-Newton observations performed until 2009, covering an area of 2.276 x 2.276 square degrees. The CFHTLS wide observations were carried out in the period between 2003 and 2008, covering an effective survey area of ~ 154 square degrees. The optical images and data of the CFHTLS were obtained with the MegaPrime instrument mounted on the CFHT in the five filters u*, g', r', i' and z'.


Catalog Bibcode

2014A&A...566A.140G

References

Mining the gap: evolution of the magnitude gap in X-ray galaxy groups from the
3-square-degree XMM coverage of CFHTLS.
    Gozaliasl G., Finoguenov A., Khosroshahi H.G., Mirkazemi M., Salvato M.,
    Jassur D.M.Z., Erfanianfar G., Popesso P., Tanaka M., Lerchster M.,
    Kneib J.P., McCracken H.J., Mellier Y., Egami E., Pereira M.J.,
    Brimioulle F., Erben T., Seitz S.
   <Astron. Astrophys., 566, A140-140 (2014)>
   =2014A&A...566A.140G    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in December 2014 based on CDS catalog J/A+A/566/A140 file table1.dat.

Parameters

Name
The XMM-Newton source designation based on its J2000.0 equatorial coordinates, e.g., 'XMMU J022538.8-050133', in the style recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

Group_ID
The internal identification of the X-ray selected galaxy group.

RA
The Right Ascension of the centroid of the X-ray source in the selected equinox. This was given in J2000.0 decimals to a precision which varied from 10-4 to 10-3 degrees in the original table.

Dec
The Declination of the centroid of the X-ray source in the selected equinox. This was given in J2000.0 decimals to a precision which varied from 10-4 to 10-2 degrees in the original table.

LII
The Galactic Longitude of the centroid of the X-ray source.

BII
The Galactic Latitude of the centroid of the X-ray source.

Phot_Redshift
The photometric redshift of the group of galaxies, estimated according to the method outlined in Section 4.1 of the reference paper.

Mass_200
The total mass, M200c, in solar masses, of the group of galaxies, obtained using the Lx - M relation of Leauthaud et al. (2010, ApJ, 709, 97).

Mass_200_Error
The statistical uncertainty in the total galaxy group mass, M200c, in solar masses). The systematic uncertainty in the inferred value of M200c using Lx is 20% (Allevato et al. 2012, ApJ, 758, 47).

Lx
The X-ray luminosity Lx of the group of galaxies, in the rest-frame 0.1 - 2.4 keV band, in erg s-1.

Lx_Error
The rms uncertainty in the X-ray luminosity of the group of galaxies, in the rest-frame 0.1 - 2.4 keV band, in erg s-1.

Sigma_Velocity
The galaxy velocity dispersion, in km s-1, estimated from Lx using the scaling relations (Erfanianfar et al. 2013, ApJ, 765, 117).

Angular_Radius_200
The angular radius, R200c, of the group of galaxies, in degrees.

kT
The mean temperature, in keV, of the group of galaxies, estimated using the L _ T relation as in Finoguenov et al. (2007, ApJS, 172, 182).

kT_Error
The rms uncertainty in the mean temperature, in keV, of the group of galaxies.

Flux
The X-ray flux of the group of galaxies in the observed 0.5 - 2 keV band, in units of ergs cm-2 s-1.

Flux_Error
The rms uncertainty in the X-ray flux of the group of galaxies in the observed 0.5 - 2 keV band, in units of ergs cm-2 s-1.

SNR
The significance of the estimate of the group X-ray flux in the observed 0.5 - 2 keV band.

Visual_Flag
This 'visual' flag (defined in Section 4.2 of the reference paper) has the following values and meanings:

    Value  Significance

       1   Unique X-ray source with a well-defined center, and a unique optical
            counterpart with the spectroscopic confirmation
       2   A single X-ray source has been split into several sources
       3   Unique X-ray source with a well-defined center, without a unique
            optical counterpart with the spectroscopic confirmation
       4   Presence of multiple optical counterparts
       5   X-ray emission covers a part of the group area and a concentration of
            galaxies is located at the edge of X-ray emission, or
            systems with a potentially wrong assignment of optical counterpart
  

Redshift
The spectroscopic redshift of the group of galaxies (available for 45 groups).

Redshift_Flag
This flag parameter is set to 'A' to indicate galaxy groups where the spectroscopic redshifts were adopted from Adami et al. (2011, A&A, 526, A18).


Contact Person

Questions regarding the CFHTLSGXMM database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Thursday, 11-Dec-2014 14:02:40 EST