Multiplicity functions of quasars: predictions from the MassiveBlackII simulation
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_{bol}> 10^{42}~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 {≲}0.7~cMpc h^{-1}; this corresponds to angular separations of ≲100 arcsec and a line-of-sight velocity difference {≲}200~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{{ per cent}} of these should be detectable in spectroscopic surveys. The simulated quasar (L_{bol}> 10^{44}~erg s^{-1}) triples and quadruples predominantly exist at 1.5 ≲ z ≲ 3. Their members have black hole masses 10^{6.5}≲ M_{ bh}≲ 109~M_{⊙ } h^{-1} and live in separate (one central and multiple satellite) galaxies with stellar masses 10^{10}≲ M_{*}≲ 10^{12}~M_{⊙ } h^{-1}. They live in the most massive haloes (e.g. {∼}10^{13}~M_{⊙ } h^{-1} at z = 2.5; {∼}10^{14}~M_{⊙ } 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2020
- DOI:
- 10.1093/mnras/staa172
- arXiv:
- arXiv:1902.05954
- Bibcode:
- 2020MNRAS.492.5620B
- Keywords:
-
- quasars: general;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 11, 10