Runaway core collapse and cluster survival: where are the parent clusters of ULXs?
| dc.creator | Soria, Roberto | |
| dc.date | 2005-03-16 | |
| dc.date.accessioned | 2026-07-07T02:17:14Z | |
| dc.date.available | 2026-07-07T02:17:14Z | |
| dc.description | Accreting intermediate-mass black holes (IMBHs) have been proposed as an explanation for ultraluminous X-ray sources (ULXs). Runaway core collapse inside a massive cluster is a possible mechanism for IMBH formation. But if so, why are ULXs only rarely found associated with a cluster? We use a simple analytical approximation to show that rapid core collapse can occur in two physical regimes. For cluster masses ~ 10^6 M_sun, an IMBH may be formed if the collapse timescale is <~ 3 Myr, as already well known; the parent cluster is expected to survive. For cluster masses ~ 10^5 M_sun, an IMBH may result from a core collapse on even shorter timescales (~ 0.5 Myr), when the protocluster is still embedded in optically thick gas. Most clusters in this latter regime are disrupted ``explosively'' as soon as the gas is ionized by the OB stars. We speculate that this process may produce isolated ULXs with masses up to a few 10^2 M_sun, surrounded by a loose OB association, and perhaps by a nebula, remnant of the expanding gas from the disrupted protocluster. | |
| dc.description | Paper presented at the XXII Texas Symposium on Relativistic Astrophysics, Stanford University, Dec. 13--17, 2004 | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0503340 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0503340 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/9098 | |
| dc.subject | Astrophysics | |
| dc.title | Runaway core collapse and cluster survival: where are the parent clusters of ULXs? | |
| dc.type | text |