Speaker: Yiming Zhong
Observations show that supermassive black holes (SMBHs) with a mass of ~10^9
solar mass exist when the Universe was just 6% of its current age. We propose a
scenario where a self-interacting dark matter halo experiences gravothermal
instability and its central region collapses into a seed black hole. The presence of
baryons in protogalaxies could significantly accelerate the gravothermal evolution
of the halo and shorten collapse timescales. The central halo could dissipate its
angular momentum remnant via viscosity induced by the self-interactions. The
host halo must be on high tails of density fluctuations, implying that high-z SMBHs
are expected to be rare in this scenario. We further derive conditions for triggering
general relativistic instability of the collapsed region. Our results indicate that self-
interacting dark matter can provide a unified explanation for diverse dark matter
distributions in galaxies today and the origin of SMBHs at redshifts z~6−7. More
details can be found in arXiv:2010.15132.