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Date and Time of the Query: 2018-11-13 T15:02:41 PST
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For refcode 2013A&A...557A..81M:
Retrieve 4199 NED objects in this reference.
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Copyright by European Southern Observatory (ESO). Reproduced by permission
2013A&A...557A..81M Classification and environmental properties of X-ray selected point-like sources in the XMM-LSS field Melnyk, O.; Plionis, M.; Elyiv, A.; Salvato, M.; Chiappetti, L.; Clerc, N.; Gandhi, P.; Pierre, M.; Sadibekova, T.; Pospieszalska-Surdej, A.; Surdej, J. Abstract. Context. The XMM-Large Scale Structure survey, covering an area of 11.1 sq. deg., contains more than 6000 X-ray point-like sources detected with the XMM-Newton to a flux of 3 x 10^-15^ erg s^-1^ cm^-2^ in the [0.5-2] keV band. The vast majority of these sources have optical (CFHTLS), infrared (SWIRE IRAC and MIPS), near-infrared (UKIDSS), and/or ultraviolet (GALEX) counterparts. Aims: We wish to investigate the environmental properties of the different types of the XMM-LSS X-ray sources by defining their environment using the i'-band CFHTLS W1 catalog of optical galaxies to a magnitude limit of 23.5 mag. Methods: We have classified 4435 X-ray selected sources on the basis of their spectra, SEDs, and X-ray luminosity, and estimated their photometric redshifts, which have a 4-11 band photometry with an accuracy of sigma_△z/(1+z_sp_)_ = 0.076 with 22.6% outliers for i' < 26 mag. We estimated the local overdensities of 777 X-ray sources that have spectro-z or photo-z calculated by using more than seven bands (accuracy of sigma_△z/(1+z_sp_)_ = 0.061 with 13.8% outliers) within the volume-limited region defined by 0.1 <= z <= 0.85 and -23.5 < M_i'_ < -20. Results: Although X-ray sources may be found in variety of environments, a high fraction (>~55-60%), as verified by comparing with the random expectations, reside in overdense regions. The galaxy overdensities within which X-ray sources reside show a positive recent redshift evolution (at least for the range studied; z <~ 0.85). We also find that X-ray selected galaxies, when compared to AGN, inhabit significantly higher galaxy overdensities, although their spatial extent appear to be smaller than that of AGN. Hard AGN (HR >= -0.2) are located in more overdense regions than soft AGN (HR < -0.2), which is clearly seen in both redshift ranges, although it appears to be stronger in the higher redshift range (0.55 < z < 0.85). Furthermore, the galaxy overdensities (with delta >~ 1.5) within which soft AGN are embedded appear to evolve more rapidly compared to the corresponding overdensities around hard AGN. Full Table 2 in only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A81 Key words: quasars: general, X-rays: general, galaxies: active, X-rays: galaxies
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