SmartStars · Pathways towards forming super-massive black holes in the early Universe

Pathways towards forming super-massive black holes in the early Universe

What is the problem being addressed? The formation mechanisms of Super-Massive Black Holes (SMBHs) in our Universe is unknown. SMBHs shining as extremely luminous quasars are seen out to very large distance and hence time. The most distant quasar thus far observed has a "redshift" of z = 7.1 meaning it existed approximately 500 Myrs after the Big Bang. This project aims to explore a promising formation mechanism - the direct collapse mechanism which has the potential to explain the formation of the very first and possibly all SMBHs. Solving this outstanding problem in modern astrophysics would unlock a significant problem in modern day black hole and galaxy formation (which is thought to be regulated by black holes). Why is it important for society? We are addressing a knowledge gap in our understanding of how the Universe operates. As a species one of our greatest strengths is our ability to understand the Universe around us. This project is attempting to shed more likely on one of the deepest mysteries in astrophysics. Black hole formation is at present poorly understood. Their existence has been confirmed through detailed observations but solid theoretical grounds explaining their formation mechanisms is still lacking. This project directly addresses this problem and with it increases our understanding of the physics of the world and Universe we inhabit. What are the overall objectives? The overall objective is to create more detailed models of black hole formation in the early Universe. The models will help to elucidate the environmental conditions that lead to massive black hole formation. Conclusions: During the course of the action I made significant progress in understanding the pathways available for SMBH formation. Early in the project I led a study showing that two galaxies forming close together in both time and space can lead to the formation of a direct collapse black hole with a seed mass sufficient to explain the origin of the most massive black holes. This research was published in Nature Astronomy and received world-wide attention both within academic circles and beyond. For a large portion of the project time I investigated the formation of super-massive stars which are though to be the progenitors of direct collapse black holes.I identified their fragmentation prospects, the formation of the first super-massive stars and their early evolution. I also investigated the initial stages of black hole formation subsequent to the collapse of the SMS. I found that powerful outflows (jets) launched by the accreting black hole regulate the average accretion rate onto the black hole to below the Eddington limit and hence present a barrier to super-Eddington accretion modes. Finally, I am the second author of another research project which has now been accepted for publication in Nature. In this research we investigate an alternate mode for forming super-massive stars in the early Universe which has the potential to open a new pathway to direct black hole formation.

Data: CORDIS, © European Union