On the growth of supermassive black holes formed from the gravitational collapse of fermionic dark matter cores

Observations support the idea that supermassive black holes (SMBHs) power the emission at the centre of active galaxies. However, contrary to stellar-mass BHs, there is a poor understanding of their origin and physical formation channel. In this article, we propose a new process of SMBH formation in the early Universe that is not associated with baryonic matter (massive stars) or primordial cosmology. In this novel approach, SMBH seeds originate from the gravitational collapse of fermionic dense dark matter (DM) cores that arise at the centre of DM haloes as they form. We show that such a DM formation channel can occur before star formation, leading to heavier BH seeds than standard baryonic channels. The SMBH seeds subsequently grow by accretion. We compute the evolution of the mass and angular momentum of the BH using a geodesic general relativistic disc accretion model. We show that these SMBH seeds grow to similar to 10(9)-10(10) M-circle dot in the first Gyr of the lifetime of the Universe without invoking unrealistic (or fine-tuned) accretion rates.

Automated summary

Observations indicate that supermassive black holes (SMBHs) drive the emissions in active galaxies. However, the origin and formation of these SMBHs are not well understood. This article proposes a new process of SMBH formation in the early Universe that does not involve baryonic matter or primordial cosmology. Instead, SMBH seeds are suggested to form from the gravitational collapse of dense dark matter cores, leading to heavier black hole seeds than those formed through baryonic channels. These SMBH seeds subsequently grow through accretion.