Supermassive black hole seeds from sub-keV dark matter

Understand

Quasars observed at redshifts $z\sim 6-7.5$ are powered by supermassive black holes which are too large to have grown from early stellar remnants without efficient super-Eddington accretion.

• A proposal for alleviating this tension is for dust and metal-free gas clouds to have undergone a process of direct collapse, producing black hole seeds of mass $M_\textrm{seed}\sim10^5 M_\odot$ around redshift $z \sim 17$.
• For direct collapse to occur, a large flux of UV photons must exist to photodissociate molecular hydrogen, allowing the gas to cool slowly and avoid fragmentation.
• We investigate the possibility of sub-keV mass dark matter decaying or annihilating to produce the UV flux needed to cause direct collapse.