Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2011-05-03
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
16 emulateapj pages, 18 figures and 3 tables. Accepted for the publication in The Astrophysical Journal
Scientific paper
We present a study of the redshift evolution of the projected correlation function of 593 X-ray selected AGN with I_AB<23 and spectroscopic redshifts z<4, extracted from the 0.5-2 keV X-ray mosaic of the 2.13 deg^2 XMM-COSMOS survey. We introduce a method to estimate the average bias of the AGN sample and the mass of AGN hosting halos, solving the sample variance using the halo model and taking into account the growth of the structure over time. We find evidence of a redshift evolution of the bias factor for the total population of XMM-COSMOS AGN from b(z=0.92)=2.30 +/- 0.11 to b(z=1.94)=4.37 +/- 0.27 with an average mass of the hosting DM halos logM [h^-1 M_sun] ~ 13.12 +/- 0.12 that remains constant at all z < 2. Splitting our sample into broad optical lines AGN (BL), AGN without broad optical lines (NL) and X-ray unobscured and obscured AGN, we observe an increase of the bias with redshift in the range z=0.7-2.25 and z=0.6-1.5 which corresponds to a constant halo mass logM [h^-1 M_sun] ~ 13.28 +/- 0.07 and logM [h^-1 M_sun] ~ 13.00 +/- 0.06 for BL /X-ray unobscured AGN and NL/X-ray obscured AGN, respectively. The theoretical models which assume a quasar phase triggered by major mergers can not reproduce the high bias factors and DM halo masses found for X-ray selected BL AGN with L_BOL ~ 2e45 erg s^-1. Our work extends up to z ~ 2.2 the z <= 1 statement that, for moderate luminosity X-ray selected BL AGN, the contribution from major mergers is outnumbered by other processes, possibly secular such as tidal disruptions or disk instabilities.
Allevato Viola
Bongiorno Angela
Brusa Marcella
Cappelluti Nico
Comastri Andrea
No associations
LandOfFree
The XMM-Newton Wide field survey in the COSMOS field: redshift evolution of AGN bias and subdominant role of mergers in triggering moderate luminosity AGN at redshift up to 2.2 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The XMM-Newton Wide field survey in the COSMOS field: redshift evolution of AGN bias and subdominant role of mergers in triggering moderate luminosity AGN at redshift up to 2.2, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The XMM-Newton Wide field survey in the COSMOS field: redshift evolution of AGN bias and subdominant role of mergers in triggering moderate luminosity AGN at redshift up to 2.2 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-692913