Star cluster migration seeds IMBHs to 10^4 solar masses in nuclei of galaxies below 5e10 solar masses by z~6
Preprint arXiv:2606.14852 presents inSpyral showing migrating star clusters seed galactic nuclei with IMBHs up to 10^4 solar masses via hierarchical mergers by z~6. This supplies a dynamical channel missing from standard SMBH growth models. Evidence rests on semi-analytic integration of L-Galaxies 2020 populations with core dynamics; main uncertainty is initial cluster size distribution.
Key limitation is the assumption of sub-parsec initial radii; larger clusters lose this advantage. Stronger evidence would come from JWST-resolved nuclear star cluster demographics at z approximately 4-7 combined with LISA IMBH merger rate forecasts. Next steps include embedding inSpyral outputs into full hydrodynamical zoom simulations to test gas and stellar feedback effects.
Torniamenti et al.: LISA will detect at least three IMBH mergers above 3000 solar masses originating in nuclei of galaxies under 5e10 solar masses within the first two years of science operations.
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2606.14852)
- [2]Supporting Source(https://arxiv.org/abs/2005.02403)