_version_ 1866912637819813888
author Jones, Brenda L.
Kocevski, Dale D.
Pacucci, Fabio
Taylor, Anthony J.
Finkelstein, Steven L.
Buchner, Johannes
Trump, Jonathan R.
Somerville, Rachel S.
Hirschmann, Michaela
Yung, L. Y. Aaron
Barro, Guillermo
Bell, Eric F.
Bisigello, Laura
Calabro, Antonello
Cleri, Nikko J.
Dekel, Avishai
Dickinson, Mark
Gandolfi, Giovanni
Giavalisco, Mauro
Grogin, Norman A.
Inayoshi, Kohei
Kartaltepe, Jeyhan S.
Koekemoer, Anton M.
Napolitano, Lorenzo
Onoue, Masafusa
Ravindranath, Swara
Rodighiero, Giulia
Wilkins, Stephen M.
author_facet Jones, Brenda L.
Kocevski, Dale D.
Pacucci, Fabio
Taylor, Anthony J.
Finkelstein, Steven L.
Buchner, Johannes
Trump, Jonathan R.
Somerville, Rachel S.
Hirschmann, Michaela
Yung, L. Y. Aaron
Barro, Guillermo
Bell, Eric F.
Bisigello, Laura
Calabro, Antonello
Cleri, Nikko J.
Dekel, Avishai
Dickinson, Mark
Gandolfi, Giovanni
Giavalisco, Mauro
Grogin, Norman A.
Inayoshi, Kohei
Kartaltepe, Jeyhan S.
Koekemoer, Anton M.
Napolitano, Lorenzo
Onoue, Masafusa
Ravindranath, Swara
Rodighiero, Giulia
Wilkins, Stephen M.
contents JWST has identified a large population of faint, broad-line active galactic nuclei (AGN) in the early universe that are powered by black holes (BHs) that often appear overmassive relative to their host galaxies. In this study, we examine the relationship between BH mass and galaxy stellar mass at $3<z<7$ using a sample of 70 broad-line AGN identified using NIRSpec/G395M spectroscopy from the CEERS, JADES, and RUBIES surveys. Roughly half (43\%) of our sample appear heavily reddened and are classified as little red dots (LRDs). We estimate BH masses ($M_{\rm BH}$) using single-epoch virial techniques, while host stellar masses ($M_{\star}$) are inferred using a combination of two-dimensional surface brightness profile fitting and spectral energy distribution modeling. We find that a majority of our sources (50/70) have $M_{\rm BH}/M_{\star}$ ratios that are 1-2 dex higher than that observed in AGN locally. Using a forward-modeling Bayesian framework that accounts for uncertainties, intrinsic scatter, and selection effects, we infer a $M_{\rm BH}-M_{\star}$ relationship that is $>3σ$ above the relationship measured for local broad-line AGN. We derive an intrinsic scatter in this relationship of $0.9$ dex, which does not vary over the redshift range of our sample. We also find that the $M_{\rm BH}/M_{\star}$ ratio increases by $2.3$ dex from $z = 3.5$ and $z = 6.5$ with a confidence level of $ > 3σ$. We attribute this trend with the increasing fraction of LRDs in our sample at $z>4$ as their host masses are $\sim1$ dex lower than the non-LRD AGN in our sample. These results support a picture in which the BHs powering JWST's broad-line AGN are genuinely overmassive and become increasingly so with redshift. We discuss the implications of our findings on early BH growth relative to that of their host galaxies and the constraints it places on BH seeding models.
format Preprint
id arxiv_https___arxiv_org_abs_2510_07376
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The $M_{\rm BH}-M_{*}$ Relationship at $3<z<7$: Big Black Holes in Little Red Dots
Jones, Brenda L.
Kocevski, Dale D.
Pacucci, Fabio
Taylor, Anthony J.
Finkelstein, Steven L.
Buchner, Johannes
Trump, Jonathan R.
Somerville, Rachel S.
Hirschmann, Michaela
Yung, L. Y. Aaron
Barro, Guillermo
Bell, Eric F.
Bisigello, Laura
Calabro, Antonello
Cleri, Nikko J.
Dekel, Avishai
Dickinson, Mark
Gandolfi, Giovanni
Giavalisco, Mauro
Grogin, Norman A.
Inayoshi, Kohei
Kartaltepe, Jeyhan S.
Koekemoer, Anton M.
Napolitano, Lorenzo
Onoue, Masafusa
Ravindranath, Swara
Rodighiero, Giulia
Wilkins, Stephen M.
Astrophysics of Galaxies
JWST has identified a large population of faint, broad-line active galactic nuclei (AGN) in the early universe that are powered by black holes (BHs) that often appear overmassive relative to their host galaxies. In this study, we examine the relationship between BH mass and galaxy stellar mass at $3<z<7$ using a sample of 70 broad-line AGN identified using NIRSpec/G395M spectroscopy from the CEERS, JADES, and RUBIES surveys. Roughly half (43\%) of our sample appear heavily reddened and are classified as little red dots (LRDs). We estimate BH masses ($M_{\rm BH}$) using single-epoch virial techniques, while host stellar masses ($M_{\star}$) are inferred using a combination of two-dimensional surface brightness profile fitting and spectral energy distribution modeling. We find that a majority of our sources (50/70) have $M_{\rm BH}/M_{\star}$ ratios that are 1-2 dex higher than that observed in AGN locally. Using a forward-modeling Bayesian framework that accounts for uncertainties, intrinsic scatter, and selection effects, we infer a $M_{\rm BH}-M_{\star}$ relationship that is $>3σ$ above the relationship measured for local broad-line AGN. We derive an intrinsic scatter in this relationship of $0.9$ dex, which does not vary over the redshift range of our sample. We also find that the $M_{\rm BH}/M_{\star}$ ratio increases by $2.3$ dex from $z = 3.5$ and $z = 6.5$ with a confidence level of $ > 3σ$. We attribute this trend with the increasing fraction of LRDs in our sample at $z>4$ as their host masses are $\sim1$ dex lower than the non-LRD AGN in our sample. These results support a picture in which the BHs powering JWST's broad-line AGN are genuinely overmassive and become increasingly so with redshift. We discuss the implications of our findings on early BH growth relative to that of their host galaxies and the constraints it places on BH seeding models.
title The $M_{\rm BH}-M_{*}$ Relationship at $3<z<7$: Big Black Holes in Little Red Dots
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2510.07376