YCAA Seminar: “Formation and growth of supermassive black holes in the early Universe”, Kohei Inayoshi - Columbia University

Event time: 
Tuesday, April 25, 2017 - 2:30pm
Hours of operation: 

coffee/tea and cookies will be served in the lounge of Steinbach Hall (52 Hillhouse) starting at 2 PM.

Watson Center (WTS), A-51 See map
60 Sachem Street
New Haven 06511
Event description: 

Supermassive black holes (SMBHs) are ubiquitously harbored at the center of present-day galaxies and believed to coevolve with their host galaxies during the cosmic history. Observations in recent decades have revealed the existence of SMBHs with billion solar masses in the early universe even at redshifts of z>6. However, this fact provides us strong constraints on their origins and growth processes because the timescale required to form such massive objects is longer than the cosmic age. I will talk about a possible scenario to explain rapid growth of seed BHs via hyper-Eddington accretion. We study gas accretion flows onto a massive BH (M_BH ~10^2-10^6 Msun) embedded in a dense gas cloud with a low abundance of metals, performing 1D/2D radiation hydrodynamical simulations. We find numerical solutions of hyper-Eddigngon accretion flows from large scales without being impeded by radiation feedback when M_BH * n_gas > 10^9 Msun cm^-3 is satisfied. In the cases, the emergent luminosity is limited below the Eddington luminosity because of photon trapping, radiation from the central region does not affect the gas dynamics at larger scales. We apply our result to the rapid formation of massive BHs in protogalaxies and discuss some observational signatures.