Title: Multiplicity functions of quasars: predictions from the MassiveBlackII simulation

Abstract

ABSTRACT We examine multiple active galactic nucleus (AGN) systems (triples and quadruples, in particular) in the MassiveBlackII simulation over a redshift range of 0.06 ≲ z ≲ 4. We identify AGN systems (with bolometric luminosity $$L_{\mathrm{bol}}\gt 10^{42}~\mathrm{erg\, s}^{-1}$$) at different scales (defined by the maximum distance between member AGNs) to determine the AGN multiplicity functions. This is defined as the volume/surface density of AGN systems per unit richness R, the number of AGNs in a system. We find that gravitationally bound multiple AGN systems tend to populate scales of $${\lesssim}0.7~\mathrm{cMpc}\, h^{-1}$$; this corresponds to angular separations of ≲100 arcsec and a line-of-sight velocity difference $${\lesssim}200~\mathrm{km\, s}^{-1}$$. The simulation contains ∼10 and ∼100 triples/quadruples per deg2 up to depths of DESI (g ≲ 24) and LSST (g ≲ 26) imaging, respectively; at least $$20{{\ \rm per\ cent}}$$ of these should be detectable in spectroscopic surveys. The simulated quasar ($$L_{\mathrm{bol}}\gt 10^{44}~\mathrm{erg\, s}^{-1}$$) triples and quadruples predominantly exist at 1.5 ≲ z ≲ 3. Their members have black hole masses $$10^{6.5}\lesssim M_{\mathrm{ bh}}\lesssim 10^{9}~\mathrm{M}_{\odot }\, h^{-1}$$ and live in separate (one central and multiple satellite) galaxies with stellar masses $$10^{10}\lesssim M_{*}\lesssim 10^{12}~\mathrm{M}_{\odot }\, h^{-1}$$. They live in the most massive haloes (e.g. $${\sim}10^{13}~\mathrm{M}_{\odot }\, h^{-1}$$ at z = 2.5; $${\sim}10^{14}~\mathrm{M}_{\odot }\, h^{-1}$$ at z = 1) in the simulation. Their detections provide an exciting prospect for understanding massive black hole growth and their merger rates in galaxies in the era of multimessenger astronomy.

Authors:

Bhowmick, Aklant K.  ^[1];

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Di Matteo, Tiziana ^[1]; Myers, Adam D. ^[2]

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1. McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
2. Department of Physics & Astronomy, University of Wyoming, 1000 University Ave., Laramie, WY 82071, USA

Publication Date:

2020-01-20

Sponsoring Org.:

USDOE

OSTI Identifier:

1598908

Grant/Contract Number:  

SC0019022

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 492 Journal Issue: 4; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English