Light or heavy supermassive black hole seeds: the role of internal rotation in the fate of supermassive stars
| Autor: | Elena M. Rossi, Davide Fiacconi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Angular momentum
Cosmology and Nongalactic Astrophysics (astro-ph.CO) Astrophysics::High Energy Astrophysical Phenomena Population FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences General Relativity and Quantum Cosmology 0103 physical sciences Galaxy formation and evolution Astrophysics::Solar and Stellar Astrophysics 010306 general physics education 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Physics High Energy Astrophysical Phenomena (astro-ph.HE) Supermassive black hole education.field_of_study Inner core Astronomy Astronomy and Astrophysics Astrophysics - Astrophysics of Galaxies Galaxy Black hole Stars Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Astrophysics::Earth and Planetary Astrophysics Astrophysics - High Energy Astrophysical Phenomena Astrophysics - Cosmology and Nongalactic Astrophysics |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY (ISSN 0035-8711), 464(2), 2259-2269 Astrophysical Journal |
| Popis: | Supermassive black holes are a key ingredient of galaxy evolution. However, their origin is still highly debated. In one of the leading formation scenarios, a black hole of $\sim100$ M$_{\odot}$ results from the collapse of the inner core of a supermassive star ($\gtrsim 10^{4-5}$ M$_{\odot}$), created by the rapid accumulation ($\gtrsim 0.1 $ M$_{\odot}$ yr$^{-1}$) of pristine gas at the centre of newly formed galaxies at $z\sim 15$. The subsequent evolution is still speculative: the remaining gas in the supermassive star can either directly plunge into the nascent black hole, or part of it can form a central accretion disc, whose luminosity sustains a surrounding, massive, and nearly hydrostatic envelope (a system called a "quasi-star"). To address this point, we consider the effect of rotation on a quasi-star, as angular momentum is inevitably transported towards the galactic nucleus by the accumulating gas. Using a model for the internal redistribution of angular momentum that qualitative matches results from simulations of rotating convective stellar envelopes, we show that quasi-stars with an envelope mass greater than a few $10^{5}$ M$_{\odot} \times (\rm black~hole~mass/100 M_{\odot})^{0.82}$ have highly sub-keplerian gas motion in their core, preventing gas circularisation outside the black hole's horizon. Less massive quasi-stars could form but last for only $\lesssim 10^4$ years before the accretion luminosity unbinds the envelope, suppressing the black hole growth. We speculate that this might eventually lead to a dual black hole seed population: (i) massive ($>10^{4}$ M$_{\odot}$) seeds formed in the most massive ($> 10^{8}$ M$_{\odot}$) and rare haloes; (ii) lighter ($\sim 10^{2}$ M$_{\odot}$) seeds to be found in less massive and therefore more common haloes. 11 pages, 5 figures, version accepted for publication in MNRAS, results unchanged, new Figure 3 |
| Databáze: | OpenAIRE |
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