SIMBAD references

2009ApJ...701.1484C - Astrophys. J., 701, 1484-1499 (2009/August-3)

AEGIS: the clustering of X-ray active galactic nucleus relative to galaxies at z ∼ 1.

COIL A.L., GEORGAKAKIS A., NEWMAN J.A., COOPER M.C., CROTON D., DAVIS M., KOO D.C., LAIRD E.S., NANDRA K., WEINER B.J., WILLMER C.N.A. and YAN R.

Abstract (from CDS):

We measure the clustering of nonquasar X-ray active galactic nucleus (AGN) at z = 0.7-1.4 in the AEGIS field. Using the cross-correlation of 113 Chandra-selected AGN, with a median log LX= 42.8 erg/s, with ∼5000 DEEP2 galaxies, we find that the X-ray AGNs are fitted by a power law with a clustering scale length of r0= 5.95±0.90 h–1 Mpc and slope γ = 1.66±0.22. X-ray AGNs have a similar clustering amplitude as red, quiescent and "green" transition galaxies at z ∼ 1 and are significantly more clustered than blue, star-forming galaxies. The X-ray AGN clustering strength is primarily determined by the host galaxy color; AGNs in red host galaxies are significantly more clustered than AGNs in blue host galaxies, with a relative bias that is similar to that of red to blue DEEP2 galaxies. We detect no dependence of clustering on optical brightness, X-ray luminosity, or hardness ratio within the ranges probed here. We find evidence for galaxies hosting X-ray AGN to be more clustered than a sample of galaxies with matching joint optical color and magnitude distributions. This implies that galaxies hosting X-ray AGN are more likely to reside in groups and more massive dark matter halos than galaxies of the same color and luminosity without an X-ray AGN. In comparison to optically selected quasars in the DEEP2 fields, we find that X-ray AGNs at z ∼ 1 are more clustered than optically selected quasars (with a 2.6σ significance) and therefore may reside in more massive dark matter halos. Our results are consistent with galaxies undergoing a quasar phase while in the blue cloud before settling on the red sequence with a lower-luminosity X-ray AGN, if they are similar objects at different evolutionary stages.

Abstract Copyright:

Journal keyword(s): galaxies: active - galaxies: high-redshift - large-scale structure of universe - X-rays: galaxies

Simbad objects: 3

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