The origin of the most massive high redshift quasars

Event Date:
2020-07-20T15:00:00
2020-07-20T16:00:00
Event Location:
Connect via zoom
Speaker:
Tyrone Woods (HAA)
Related Upcoming Events:
Intended Audience:
Undergraduate
Local Contact:

Douglas Scott

Event Information:

The discovery of billion solar mass quasars at redshifts of 6–7 challenges our understanding of the early Universe; how did such massive objects form in the first billion years? Observational constraints and numerical simulations increasingly favour the "direct collapse" scenario. In this case, an atomically-cooled halo of primordial composition accretes rapidly onto a single protostellar core, ultimately collapsing through the Chandrasekhar-Feynman instability to produce a supermassive (~100,000 solar mass) "seed" black hole. In this talk, I will present a systematic study of the lives and deaths of these objects, including post-Newtonian corrections to gravity and a detailed treatment of nuclear burning processes using an adaptive network. We find a simple relation between the infall rate and the final mass at collapse, rule out the existence of rapidly-rotating supermassive stars, and delineate the regimes for which objects either undergo "truly direct" collapse or survive to long-lived nuclear-burning under differing formation scenarios. I will also discuss the possibility of early chemical enrichment from these objects, observational prospects in the era of the JWST, and briefly summarize other future directions.

Add to Calendar 2020-07-20T15:00:00 2020-07-20T16:00:00 The origin of the most massive high redshift quasars Event Information: The discovery of billion solar mass quasars at redshifts of 6–7 challenges our understanding of the early Universe; how did such massive objects form in the first billion years? Observational constraints and numerical simulations increasingly favour the "direct collapse" scenario. In this case, an atomically-cooled halo of primordial composition accretes rapidly onto a single protostellar core, ultimately collapsing through the Chandrasekhar-Feynman instability to produce a supermassive (~100,000 solar mass) "seed" black hole. In this talk, I will present a systematic study of the lives and deaths of these objects, including post-Newtonian corrections to gravity and a detailed treatment of nuclear burning processes using an adaptive network. We find a simple relation between the infall rate and the final mass at collapse, rule out the existence of rapidly-rotating supermassive stars, and delineate the regimes for which objects either undergo "truly direct" collapse or survive to long-lived nuclear-burning under differing formation scenarios. I will also discuss the possibility of early chemical enrichment from these objects, observational prospects in the era of the JWST, and briefly summarize other future directions. Event Location: Connect via zoom