SMBH Seeds from Dissipative Dark Matter

TL;DR

This paper proposes that dissipative self-interacting dark matter can form supermassive black hole seeds in the early universe through catastrophic collapse, explaining high-redshift SMBHs while aligning with late-time observations.

Contribution

It introduces a semi-analytic model calibrated with N-body simulations to demonstrate how dissipative dark matter can produce SMBH seeds in the early universe.

Findings

Dissipative dark matter with cross-section ~0.05 cm^2/g can produce observed high-redshift SMBHs.

Model predictions match observed quasar luminosity functions and SMBH mass relations.

The scenario is consistent with SMBH populations in both early and late universe.

Abstract

The existence of supermassive black holes (SMBHs) with masses greater than $\sim 10^{9}M_{\odot}$ at high redshift ($z\gtrsim 7$) is difficult to accommodate in standard astrophysical scenarios. We study the possibility that (nearly) totally dissipative self-interacting dark matter (tdSIDM)--in rare, high density dark matter fluctuations in the early Universe--produces SMBH seeds through catastrophic collapse. We use a semi-analytic model, tested and calibrated by a series of N-body simulations of isolated dark matter halos, to compute the collapse criteria and timescale of tdSIDM halos, where dark matter loses nearly all of its kinetic energy in a single collision in the center-of-momentum frame. Applying this model to halo merger trees, we empirically assign SMBH seeds to halos and trace the formation and evolution history of SMBHs. We make predictions for the quasar luminosity function, the $M_{\rm BH}$-$\sigma_{\rm v}^{\ast}$ relation, and cosmic SMBH mass density at high redshift and compare them to observations. We find that a dissipative dark matter interaction cross-section of $\sigma/m \sim 0.05~\rm cm^2/g$ is sufficient to produce the SMBHs observed in the early Universe while remaining consistent with ordinary SMBHs in the late Universe.