Little Red Dots are Tidal Disruption Events in Runaway-Collapsing Clusters

Jillian Bellovary

First listed 2025-01-06 | Last updated 2025-04-22

Abstract

I hypothesize a physical explanation for the "Little Red Dots" (LRDs) discovered by the James Webb Space Telescope (JWST). The first star formation in the universe occurs in dense clusters, some of which may undergo runaway collapse and form an intermediate mass black hole. This process would appear as a very dense stellar system, with recurring tidal disruption events (TDEs) as stellar material is accreted by the black hole. Such a system would be compact, UV-emitting, and exhibit broad H-alpha emission. If runaway collapse is the primary mechanism for forming massive black hole seeds, this process could be fairly common and explain the large volume densities of LRDs. In order to match the predicted number density of runaway collapse clusters, the tidal disruption rate must be on the order of 10^-4 per year. A top-heavy stellar initial mass function may be required to match observations without exceeding the predicted LambdaCDM mass function. The TDE LRD hypothesis can be verified with followup JWST observations looking for TDE-like variability.

Short digest

Proposes that Little Red Dots are recurrent tidal disruption events triggered during runaway collapse of the first dense star clusters, forming intermediate-mass black hole seeds. Matching JWST LRD number densities to seed-formation predictions implies a required TDE rate of ~10^-4 yr^-1; analytic (loss-cone) and simulation-based scalings show this rate is feasible in dense clusters. The scenario naturally explains compact, UV-bright emission with broad H-alpha and links LRDs to early black-hole growth. A top-heavy IMF may be needed to satisfy ΛCDM mass-function limits, and the hypothesis is testable via TDE-like variability in JWST follow-up.

Key figures to inspect

• Figure 1: Compare LRD comoving number densities against analytic and simulation seed-formation curves to see the ~4 dex shortfall that motivates a TDE duty cycle of ~10^-4 yr^-1.
• Figure 2 (top): TDE rate versus black hole mass at fixed σ; identify the IMBH mass range where both Stone+2017 and Rizzuto+2023 prescriptions achieve ~10^-4 yr^-1 under the adopted dense-cluster conditions.
• Figure 2 (bottom): TDE rate versus stellar velocity dispersion at fixed MBH; check that σ≈100–150 km s^-1 yields the target ~10^-4 yr^-1, supporting feasibility in compact, high-density clusters.