CFHTLSGXMM - XMM-Newton CFHTLS W1 Field Galaxy Groups Catalog
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'.
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)
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.
The internal identification of the X-ray selected galaxy group.
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.
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.
The Galactic Longitude of the centroid of the X-ray source.
The Galactic Latitude of the centroid of the X-ray source.
The photometric redshift of the group of galaxies, estimated according to the method outlined in Section 4.1 of the reference paper.
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).
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).
The X-ray luminosity Lx of the group of galaxies, in the rest-frame 0.1 - 2.4 keV band, in erg s-1.
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.
The galaxy velocity dispersion, in km s-1, estimated from Lx using the scaling relations (Erfanianfar et al. 2013, ApJ, 765, 117).
The angular radius, R200c, of the group of galaxies, in degrees.
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).
The rms uncertainty in the mean temperature, in keV, of the group of galaxies.
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.
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.
The significance of the estimate of the group X-ray flux in the observed 0.5 - 2 keV band.
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
The spectroscopic redshift of the group of galaxies (available for 45 groups).
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).