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# Clustering of moderate luminosity X-ray-selected Type 1 and Type 2 AGNS at Z ~ 3

Allevato, V., Finoguenov, A., Civano, F., Cappelluti, N., Shankar, F., Miyaji, T., Hasinger, G., Gilli, R., Zamorani, G., Lanzuisi, G., Salvato, M., Elvis, M., Comastri, A. and Silverman, J. (2014) Clustering of moderate luminosity X-ray-selected Type 1 and Type 2 AGNS at Z ~ 3. The Astrophysical Journal, 796 (1), 4.

Record type: Article

## Abstract

We investigate, for the first time at z ~ 3, the clustering properties of 189 Type 1 and 157 Type 2 X-ray active galactic nuclei (AGNs) of moderate luminosity (langL bolrang = 1045.3 erg s–1), with photometric or spectroscopic redshifts in the range 2.2 < z < 6.8. These samples are based on Chandra and XMM-Newton data in COSMOS. We find that Type 1 and Type 2 COSMOS AGNs at z ~ 3 inhabit DMHs with typical mass of log Mh = 12.84$^{+0.10}_{-0.11}$ and 11.73$^{+0.39}_{-0.45}$ h –1 M ☉, respectively. This result requires a drop in the halo masses of Type 1 and 2 COSMOS AGNs at z ~ 3 compared to z lesssim 2 XMM-COSMOS AGNs with similar luminosities. Additionally, we infer that unobscured COSMOS AGNs at z ~ 3 reside in 10 times more massive halos compared to obscured COSMOS AGNs, at the 2.6σ level. This result extends to z ~ 3 the results found in COSMOS at z lesssim 2, and rules out the picture in which obscuration is purely an orientation effect. A model which assumes that the AGNs activity is triggered by major mergers is quite successful in predicting both the low halo mass of COSMOS AGNs and the typical mass of luminous SDSS quasars at z ~ 3, with the latter inhabiting more massive halos respect to moderate luminosity AGNs. Alternatively we can argue, at least for Type 1 COSMOS AGNs, that they are possibly representative of an early phase of fast (i.e., Eddington limited) BH growth induced by cosmic cold flows or disk instabilities. Given the moderate luminosity, these new fast growing BHs have masses of ~107-8 M ☉ at z ~ 3 which might evolve into ~108.5-9 M ☉ mass BHs at z = 0. Following our clustering measurements, we argue that this fast BH growth at z ~ 3 in AGNs with moderate luminosity occurs in DMHs with typical mass of ~ 6× 1012 h –1 M ☉.

Published date: 1 November 2014

## Identifiers

Local EPrints ID: 439344
URI: http://eprints.soton.ac.uk/id/eprint/439344
ISSN: 0004-637X
PURE UUID: 6e67a1e4-f93e-480f-8976-45cf0885dea6

## Catalogue record

Date deposited: 17 Apr 2020 16:30

## Contributors

Author: V. Allevato
Author: A. Finoguenov
Author: F. Civano
Author: N. Cappelluti
Author: F. Shankar
Author: T. Miyaji
Author: G. Hasinger
Author: R. Gilli
Author: G. Zamorani
Author: G. Lanzuisi
Author: M. Salvato
Author: M. Elvis
Author: A. Comastri
Author: J. Silverman