The Sloan Digital Sky Survey Reverberation Mapping Project: The Black Hole Mass–Stellar Mass Relations at 0.2 ≲ z ≲ 0.8

Abstract

We measure the correlation between black hole mass M BH and host stellar mass M * for a sample of 38 broad-line quasars at 0.2 ≲ z ≲ 0.8 (median redshift z med = 0.5). The black hole masses are derived from a dedicated reverberation mapping program for distant quasars, and the stellar masses are derived from two-band optical+IR Hubble Space Telescope imaging. Most of these quasars are well centered within ≲1 kpc from the host galaxy centroid, with only a few cases in merging/disturbed systems showing larger spatial offsets. Our sample spans two orders of magnitude in stellar mass (∼109–1011 M ⊙) and black hole mass (∼107–109 M ⊙) and reveals a significant correlation between the two quantities. We find a best-fit intrinsic (i.e., selection effects corrected) M BH–M *,host relation of log ( M BH / M ⊙ ) = 7.01 − 0.33 + 0.23 + 1.74 − 0.64 + 0.64 log ( M * , host / 10 10 M ⊙ ) , with an intrinsic scatter of 0.47 − 0.17 + 0.24 dex. Decomposing our quasar hosts into bulges and disks, there is a similar M BH–M *,bulge relation with slightly larger scatter, likely caused by systematic uncertainties in the bulge–disk decomposition. The M BH–M *,host relation at z med = 0.5 is similar to that in local quiescent galaxies, with negligible evolution over the redshift range probed by our sample. With direct black hole masses from reverberation mapping and the large dynamical range of the sample, selection biases do not appear to affect our conclusions significantly. Our results, along with other samples in the literature, suggest that the locally measured black hole mass–host stellar mass relation is already in place at z ∼ 1.

Characterization of JWST NIRCam PSFs and Implications for AGN+host Image Decomposition

“…Comparing with the local M BH -M * relation from inactive galaxies in Greene et al (2020), we find that this object lies ∼0.6 dex above the upper envelope (best-fit relation + 1 × intrinsic scatter) of local latetype (spiral) galaxies, but consistent with early-type (elliptical and S0) galaxies (Figure 18). The position of this object is in broad agreement with previous studies with host fluxes derived from image decomposition using X-ray selected broad-line AGNs at similar redshifts (e.g., Jahnke et al 2009;Bennert et al 2011;Schramm & Silverman 2013;Ding et al 2020;Zhuang et al 2024) and SDSS-RM quasars at 0.2  z  0.8 (Li et al 2023) with M BH from reverberation mapping. An increase of at least 0.4 dex in M * is required to reconcile this object with the local relation for late-type galaxies.…”

“…For high-resolution imaging analyses with HST or JWST data, it is customary to build empirical PSF models using a library of PSF sources (e.g., Ding et al 2022;Li et al 2023). The major benefit of these PSF models is that they can mitigate the noise in the low surface brightness (SB) wings of the PSF, compared with PSF templates directly based on observed stars.…”

“…We recalculated their M BH using Equation (5) from Woo et al (2015) to match the choice of virial factor adopted for SDSS 1420+5300A in Grier et al (2019). Filled triangles represent SDSS-RM quasars at 0.2  z  0.8 with M BH from reverberation mapping in Li et al (2023). Typical uncertainties are indicated in the lower-right corner.…”

Active Galactic Nuclei and Host Galaxies in COSMOS-Web. I. NIRCam Images, Point-spread-function Models and Initial Results on X-Ray-selected Broad-line AGNs at 0.35 ≲ z ≲ 3.5

“…This fraction is in broad agreement with AGNs in the nearby Universe and at 1 < z < 3 (e.g., Fan et al 2014;Rosario et al 2015;Ding et al 2020;J. Li et al 2021b;Bennert et al 2021;Kim et al 2021;Li et al 2023;Zhuang & Ho 2023), suggesting no significant redshift evolution of Sérsic index of AGNhost galaxies.…”

“…The long tail of the distribution is due to a combination of faint nucleus and asymmetric light distribution from interactions (Section 6.2). Nonetheless, the high resolution of JWST NIRCam provides more stringent constraints on AGN-host offset compared to previous results based on HST images and Gaia astrometry (e.g., Shen et al 2019;Li et al 2023). Therefore, our results suggest that there is no significant AGN-host offset in the majority of X-ray broad-line AGNs.…”