ChandraCOSMOS Legacy Survey: Clustering dependence of Type 2 active galactic nuclei on host galaxy properties

Abstract

Aims. We perform clustering measurements of 800 X-ray selected Chandra COSMOS Legacy (CCL) Type 2 AGN with known spectroscopic redshift to probe the halo mass dependence on AGN host galaxy properties, such as galaxy stellar mass M star , star formation rate (SFR) and specific black hole accretion rate λ BHAR , in the redshift range z = [0 -3]. Methods. We split the sample of AGN with known spectroscopic redshits according to M star , SFR and λ BHAR , while matching the distributions in terms of the other parameters, including redshift. We measure the projected two-point correlation function w p (r p ) and model it with the 2-halo term to derive the large-scale bias b and the corresponding typical mass of the hosting halo, for the different subsamples.Results. We found no significant dependence of the large-scale bias and typical halo mass on galaxy stellar mass and specific BHAR for CCL Type 2 AGN at mean z∼1, while a negative dependence on SFR is observed, with lower SFR AGN residing in richer environment. Mock catalogs of AGN matched to have the same X-ray luminosity, stellar mass, λ BHAR and SFR of CCL Type 2 AGN, almost reproduce the observed M star − M h , λ BHAR − M h and SFR-M h relations, when assuming a fraction of satellite AGN f sat AGN ∼ 0.15, which corresponds to a ratio between the probabilities of satellite and central AGN of being active Q ∼ 2. Mock matched normal galaxies follow a slightly steeper M star − M h relation -with low mass mock galaxies residing in less massive halos than mock AGN of similar mass, and are less biased than mock AGN with similar specific BHAR and SFR, at least for Q > 1.

Surveys of the Cosmic X-ray Background

“…Host-galaxy stellar mass and star-formation rate: As we have discussed in §3.1, both SMBH growth and galaxy stellar growth have the anti-hierarchical behavior of downsizing. Also, the cosmic SMBH-accretion density and star-formation density 3 both peak at z ≈ 2 (see, e.g., Fig. 20 of Aird et al 2015).…”

The role of scatter and satellites in shaping the large-scale clustering of X-ray AGN as a function of host galaxy stellar mass

“…For building mock catalogs of AGNs, we start from the dark matter (DM) halo catalog extracted from the MultiDark Planck 2 (MDPL2) simulation (Riebe et al 2013;Klypin et al 2016) at redshift 𝑧 = 1.22, close to the redshift of recent X-ray AGN clustering measurements (e.g. Viitanen et al 2019;Allevato et al 2019). The MDPL2 simulation is a cosmological DM only N-body simulation, with a box size of 1 Gpc/ℎ, 3 840 3 DM particles, and a mass resolution of 1.51 × 10 9 M /ℎ.…”

“…Finally, we follow Allevato et al (2019) and assign an obscuration value 𝑁 H to each BH based on AGN luminosity following Ueda et al (2014).…”

“…Georgakakis et al 2019;Aird & Coil 2021;Allevato et al 2021) Further constraints on the co-evolution scenario are indeed provided by studying the spatial clustering of AGN, especially X-ray selected (e.g. Coil et al 2009;Krumpe et al 2010;Allevato et al 2011;Krumpe et al 2012;Mountrichas & Georgakakis 2012;Mendez et al 2016;Powell et al 2018;Viitanen et al 2019;Allevato et al 2019;Powell et al 2020). Clustering provides an independent way of connecting accreting BHs to their large-scale environments via the link with their underlying dark matter halo population.…”

“…In particular, several AGN clustering studies have specifically considered AGN clustering as a function of the host galaxy stellar mass (e.g. Georgakakis et al 2014;Mountrichas et al 2019;Viitanen et al 2019;Allevato et al 2019). Moreover, in the next years the synergy among J-PAS, eROSITA, 4MOST, LSST, Euclid, and JWST will allow us to measure the AGN clustering with high statistics, and to derive host galaxy stellar mass estimates of moderate-to-high luminosity AGN up to 𝑧 ∼ 2 to measure the large-scale bias as a function of host galaxy properties of millions of objects at different 𝑧.…”