THE HALO OCCUPATION DISTRIBUTION OF X-RAY-BRIGHT ACTIVE GALACTIC NUCLEI: A COMPARISON WITH LUMINOUS QUASARS

Journal Article · Tue Sep 10 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/774/2/143· OSTI ID:22133863

Richardson, Jonathan ^[1]; Chatterjee, Suchetana; Myers, Adam D. ^[2]; Zheng, Zheng ^[3]; Hickox, Ryan ^[4]

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1. Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60605 (United States)
2. Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82072 (United States)
3. Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)
4. Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

We perform halo occupation distribution (HOD) modeling of the projected two-point correlation function (2PCF) of high-redshift (z {approx} 1.2) X-ray-bright active galactic nuclei (AGNs) in the XMM-COSMOS field measured by Allevato et al. The HOD parameterization is based on low-luminosity AGNs in cosmological simulations. At the median redshift of z {approx} 1.2, we derive a median mass of 1.02{sub -0.23}{sup +0.21} Multiplication-Sign 10{sup 13} h{sup -1} M{sub sun} for halos hosting central AGNs and an upper limit of {approx}10% on the AGN satellite fraction. Our modeling results indicate (at the 2.5{sigma} level) that X-ray AGNs reside in more massive halos compared to more bolometrically luminous, optically selected quasars at similar redshift. The modeling also yields constraints on the duty cycle of the X-ray AGN, and we find that at z {approx} 1.2 the average duration of the X-ray AGN phase is two orders of magnitude longer than that of the quasar phase. Our inferred mean occupation function of X-ray AGNs is similar to recent empirical measurements with a group catalog and suggests that AGN halo occupancy increases with increasing halo mass. We project the XMM-COSMOS 2PCF measurements to forecast the required survey parameters needed in future AGN clustering studies to enable higher precision HOD constraints and determinations of key physical parameters like the satellite fraction and duty cycle. We find that N {sup 2}/A {approx} 5 Multiplication-Sign 10{sup 6} deg{sup -2} (with N the number of AGNs in a survey area of A deg{sup 2}) is sufficient to constrain the HOD parameters at the 10% level, which is easily achievable by upcoming and proposed X-ray surveys.

• OSTI ID: 22133863
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 774; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCURACY
GALAXY NUCLEI
LIMITING VALUES
LUMINOSITY
QUASARS
RED SHIFT
SATELLITES
SIMULATION
X RADIATION