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SUMMARY:Forming intermediate mass black holes in assembling star clusters 
 - Antti Rantala (IoA / KICC)
DTSTART:20260212T123000Z
DTEND:20260212T133000Z
UID:TALK243628@talks.cam.ac.uk
CONTACT:Mika Kontiainen
DESCRIPTION:We explore the formation of intermediate mass black holes (IMB
 Hs)\, potential seeds for supermassive black holes (SMBHs)\, via runaway s
 tellar collisions for a wide range of star cluster densities and metallici
 ties. Our sample of isolated (>1400) and hierarchical (30) simulations of 
 young\, massive star clusters with up to 1.8 million stars includes collis
 ional stellar dynamics\, stellar evolution\, and post-Newtonian equations 
 of motion for black holes using the BIFROST code. High stellar wind rates 
 suppress IMBH formation at high metallicities (above 0.2 of the solar valu
 e) and low collision rates prevent their formation at low densities. The a
 ssumptions about stellar wind loss rates strongly affect the final IMBH ma
 sses (6000 vs 25000 solar masses). We present fitting formulae for IMBH ma
 sses as a function of host star cluster properties\, and formulate a simpl
 e model for the cosmic IMBH formation rate density.
LOCATION:Institute of Astronomy 
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