Synchronized Coevolution between Supermassive Black Holes and Galaxies over the Last Seven Billion Years as Revealed by Hyper Suprime-Cam
Abstract
We measure the evolution of the ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$ relation using 584 uniformly selected Sloan Digital Sky Survey quasars at 0.2 < z < 0.8. The black hole masses ( ${{ \mathcal M }}_{\mathrm{BH}}$ ) are derived from the single-epoch virial mass estimator using the Hβ emission line and span the range $7.0\lt \mathrm{log}\,{{ \mathcal M }}_{\mathrm{BH}}/{M}_{\odot }\lt 9.5$ . The host-galaxy stellar masses ( ${{ \mathcal M }}_{\star }$ ), which cover the interval $10.0\lt \mathrm{log}\,{{ \mathcal M }}_{\star }/{M}_{\odot }\lt 11.5$ , are determined by performing two-dimensional quasar-host decomposition of the Hyper Suprime-Cam images and spectral energy distribution fitting. To quantify sample selection biases and measurement uncertainties on the mass terms, a mock quasar sample is constructed to jointly constrain the redshift evolution of the ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$ relation and its intrinsic scatter (σ μ ) through forward modeling. We find that the level of evolution is degenerate with σ μ , such that both a positive mild evolution (i.e., ${{ \mathcal M }}_{\mathrm{BH}}/{{ \mathcal M }}_{\star }$ increases with redshift) with a small σ μ and a negative mild evolution with a larger σ μ are consistent with our data. The posterior distribution of σ μ enables us to put a strong constraint on the intrinsic scatter of the ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$ relation, which has a best inference of ${0.25}_{-0.04}^{+0.03}$ dex, consistent with the local value. The redshift evolution of the ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$ relation relative to the local relation is constrained to be ${\left(1+z\right)}^{{0.12}_{-0.27}^{+0.28}}$ , in agreement with no significant evolution since z ~ 0.8. The tight and unevolving ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\star }$ relation is suggestive of a coupling through active galactic nuclei feedback or/and a common gas supply at work, thus restricting the mass ratio of galaxies and their black holes to a limited range. Given the considerable stellar disk component, the ${{ \mathcal M }}_{\mathrm{BH}}\mbox{--}{{ \mathcal M }}_{\mathrm{bulge}}$ relation may evolve as previously seen at higher redshifts.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2021
- DOI:
- 10.3847/1538-4357/ac2301
- arXiv:
- arXiv:2109.02751
- Bibcode:
- 2021ApJ...922..142L
- Keywords:
-
- 2017;
- 16;
- 1663;
- 1319;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 17 pages, 6 figures, accepted by ApJ