Seminar 6/10/17: Formation and Growth of the first Black Holes

Formation and Growth of the first Black Holes
John Regan
Dublin City University
Friday 6 October 2017
1pm, Blue Room, 4th floor, Main Building, DIT Kevin Street

Abstract:

The discovery of supermassive black holes (SMBHs) at high-z (z ≥ 6) is a direct challenge to our understanding of the formation of the structure at small scales in the Universe (first stars, galaxies and black holes). The first stars are expected to form in mini-haloes where a combination of gravity and gas chemistry result in the first runaway collapse. These first stars may be massive with characteristic masses in the region of 50 Msolar. However, the observations of SMBHs with masses of 1 billion solar masses shortly after when we expect the first stars to form is perplexing.

I will discuss possible solutions to this problem. In particular I will discuss forming unusually massive stars in the early Universe which could explain the high-z SMBHs and also importantly the growth requirements subsequently (from either PopIII stars or supermassive stars) – which will likely require periods of super-critical growth.