The Stellar MassBlack Hole Mass Relation at z 2 down to {{M }}_{\mathrm{BH}}∼ {10}(7} {M) _{⊙ } Determined by HETDEX
Abstract
We investigate the stellar massblack hole mass ( ${{ \mathcal M }}_{* }\mbox{}{{ \mathcal M }}_{\mathrm{BH}}$ ) relation with type 1 active galactic nuclei (AGNs) down to ${{ \mathcal M }}_{\mathrm{BH}}={10}^{7\,}{M}_{\odot }$ , corresponding to a ≃ 21 absolute magnitude in restframe ultraviolet, at z = 22.5. Exploiting the deep and largearea spectroscopic survey of the HobbyEberly Telescope Dark Energy Experiment (HETDEX), we identify 66 type 1 AGNs with ${{ \mathcal M }}_{\mathrm{BH}}$ ranging from 10^{7}10^{10} M _{⊙} that are measured with singleepoch virial method using C IV emission lines detected in the HETDEX spectra. ${{ \mathcal M }}_{* }$ of the host galaxies are estimated from optical to nearinfrared photometric data taken with Spitzer, the Widefield Infrared Survey Explorer, and groundbased 48 m class telescopes by CIGALE spectral energy distribution (SED) fitting. We further assess the validity of SED fitting in two cases by hostnuclear decomposition performed through surface brightness profile fitting on spatially resolved host galaxies with the James Webb Space Telescope/NIRCam CEERS data. We obtain the ${{ \mathcal M }}_{* }\mbox{}{{ \mathcal M }}_{\mathrm{BH}}$ relation covering the unexplored lowmass ranges of ${{ \mathcal M }}_{\mathrm{BH}}\,\sim \,{10}^{7}\mbox{}{10}^{8}\,{M}_{\odot }$ , and conduct forward modeling to fully account for the selection biases and observational uncertainties. The intrinsic ${{ \mathcal M }}_{* }\mbox{}{{ \mathcal M }}_{\mathrm{BH}}$ relation at z ~ 2 has a moderate positive offset of 0.52 ± 0.14 dex from the local relation, suggestive of more efficient black hole growth at higher redshift even in the lowmass regime of ${{ \mathcal M }}_{\mathrm{BH}}\,\sim \,{10}^{7}\mbox{}{10}^{8}\,{M}_{\odot }$ . Our ${{ \mathcal M }}_{* }\mbox{}{{ \mathcal M }}_{\mathrm{BH}}$ relation is inconsistent with the ${{ \mathcal M }}_{\mathrm{BH}}$ suppression at the low ${{ \mathcal M }}_{* }$ regime predicted by recent hydrodynamic simulations at a 98% confidence level, suggesting that feedback in the lowmass systems may be weaker than those produced in hydrodynamic simulations.
 Publication:

The Astrophysical Journal
 Pub Date:
 May 2023
 DOI:
 10.3847/15384357/acc2c2
 arXiv:
 arXiv:2303.02929
 Bibcode:
 2023ApJ...948..103Z
 Keywords:

 Galaxy evolution;
 AGN host galaxies;
 Active galactic nuclei;
 Supermassive black holes;
 594;
 2017;
 16;
 1663;
 Astrophysics  Astrophysics of Galaxies
 EPrint:
 16 pages, 8 figures, accepted for publication in ApJ