Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). XVIII. The Dark Matter Halo Mass of Quasars at z 6
Abstract
We present, for the first time, dark matter halo (DMH) mass measurement of quasars at z ~ 6 based on a clustering analysis of 107 quasars. Spectroscopically identified quasars are homogeneously extracted from the Hyper Suprime-Cam Strategic Survey Program wide layer over 891 deg2. We evaluate the clustering strength by three different autocorrelation functions: projected correlation function, angular correlation function, and redshift-space correlation function. The DMH mass of quasars at z ~ 6 is evaluated as ${5.0}_{-4.0}^{+7.4}\times {10}^{12}\,{h}^{-1}{M}_{\odot }$ with the bias parameter b = 20.8 ± 8.7 by the projected correlation function. The other two estimators agree with these values; though, each uncertainty is large. The DMH mass of quasars is found to be nearly constant ~1012.5 h -1 M ⊙ throughout cosmic time, suggesting that there is a characteristic DMH mass where quasars are always activated. As a result, quasars appear in the most massive halos at z ~ 6, but in less extreme halos thereafter. The DMH mass does not appear to exceed the upper limit of 1013 h -1 M ⊙, which suggests that most quasars reside in DMHs with ${M}_{\mathrm{halo}}\lt {10}^{13}{h}^{-1}{M}_{\odot }$ across most of the cosmic time. Our results supporting a significant increasing bias with redshift are consistent with the bias evolution model with inefficient active galactic nucleus feedback at z ~ 6. The duty cycle (f duty) is estimated as 0.019 ± 0.008 by assuming that DMHs in some mass interval can host a quasar. The average stellar mass is evaluated from stellar-to-halo mass ratio as ${M}_{* }={6.5}_{-5.2}^{+9.6}\times {10}^{10}\,{h}^{-1}{M}_{\odot }$ , which is found to be consistent with [C II] observational results.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2023
- DOI:
- 10.3847/1538-4357/ace43a
- arXiv:
- arXiv:2307.02531
- Bibcode:
- 2023ApJ...954..210A
- Keywords:
-
- Large-scale structure of the universe;
- Quasars;
- Supermassive black holes;
- 902;
- 1319;
- 1663;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 22 pages, 8 figures, accepted for publication in ApJ