Constraints on Dark Matter Models from Supermassive Black Hole Evolution

Abstract

A semi-analytical model for the evolution of galaxies and supermassive black holes (SMBHs) within the $Λ$CDM paradigm has been shown to yield stellar mass-BH mass relations that reproduce both the JWST and pre-JWST observations. Either fuzzy or warm dark matter (FDM or WDM) would suppress the formation of the smaller galactic halos that play important roles in the CDM fit to the high-redshift SMBH data. Our analysis of the stellar mass-BH mass relation disfavours FDM fields with masses $< 2.0\times 10^{-20}$ eV and WDM particles with masses $< 7.2$ keV, both at the 95 % confidence level.

Figures (7)

• Figure 1: Stellar mass-BH mass relation in a heavy-seed scenario. Solid lines show the CDM results and dashed lines the FDM result with $m_{\rm FDM}=10^{-21}\,{\rm eV}$. The different colours in the top panel represent the different redshifts, while the lower panel represents the local universe.
• Figure 2: Growth of individual SMBHs in both the light and heavy seed scenarios (orange and blue, respectively). CDM calculations are shown with solid curves and FDM with dashed ($m_{\rm FDM} = 10^{-19}$ eV) and dotted ($m_{\rm FDM} = 10^{-21}$ eV) curves. The host DM halo mass at $z=0$ is fixed to $M_{\rm v} = 10^{13}\,M_\odot$.
• Figure 3: Posteriors of the stellar mass-BH mass fit parameters as functions of the FDM mass (upper panels) and WDM mass (lower panels). The vertical dashed lines are our 95% CL lower bouds on these masses. The grey band in the $\log_{10}(m_{\rm FDM}/{\rm eV})$ posterior shows the most stringent 95$\%\, {\rm CL}$ exclusion of $m_{\rm FDM}$ from a Lyman-$\alpha$ analysis Irsic:2017yje, namely $< 2\times10^{-20}\,{\rm eV}$, and the grey band in the $\log_{10}(m_{\rm WDM}/{\rm keV})$ posterior shows the most stringent 95$\%\, {\rm CL}$ exclusion of $m_{\rm WDM}$ from a joint analysis of strong gravitational lensing, the Lyman-$\alpha$ forest and Milky Way satellites Enzi:2020ieg, namely $< 6.0\,{\rm keV}$. The full corner plots are shown in the Supplemental Material Ellis2026.
• Figure S1: The dotted curves in three colours corresponding to different redshifts show the SFR fitted to the UV luminosity function data, and the solid curves show the remaining gas fraction available for SMBH accretion at different redshifts.
• Figure S2: Posteriors of the stellar mass-BH mass relation fit in a CDM universe. The contours indicate the 68% and 95% credible regions. The grey dashed region in the $\log_{10}(M_{\rm seed}/M_{\odot})$ posterior represents the range of values given in the literature for this parameter 2007MNRAS.377..667N2021MNRAS.507.1775S2021ApJ...917...40K, the two red dashed lines correspond to the values given in 2019MNRAS.486.2336D to match the AGN luminosity function. The grey range on $p_{\rm BH}$ is the range that gives the correct PTA gravitational wave background strength according to Ellis:2023dgf.