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SUMMARY:Effects of primordial black holes on early star formation - Boyuan
  Liu (IoA)
DTSTART:20240315T113000Z
DTEND:20240315T123000Z
UID:TALK211609@talks.cam.ac.uk
CONTACT:Sandro Tacchella
DESCRIPTION:Primordial black holes (PBHs) have long been considered a prom
 ising candidate or an important component of dark matter (DM). Recent grav
 itational wave (GW) observations of binary black hole (BH) mergers have tr
 iggered renewed interest in PBHs in the stellar-mass (∼ 10 − 100 Msun)
  and supermassive regimes (∼ 10^7 − 10^11 Msun). Although only a small
  fraction (≲ 1%) of dark matter in the form of PBHs is required to expla
 in observations\, these PBHs may play important roles in early structure/s
 tar formation. We use cosmological zoom-in simulations and semi-analytical
  models to explore the possible impact of stellar-mass PBHs on first star 
 formation\, taking into account two effects of PBHs: acceleration of struc
 ture formation and gas heating by BH accretion feedback. We find that the 
 standard picture of first star formation is not changed by stellar-mass PB
 Hs (allowed by existing observational constraints)\, and their global impa
 ct on the cosmic star formation history is likely minor. However\, PBHs do
  alter the properties of the first star-forming halos and can potentially 
 trigger the formation of direct-collapse BHs in atomic cooling halos. On t
 he other hand\, supermassive PBHs may play more important roles as seeds o
 f massive structures that can explain the apparent overabundance of massiv
 e galaxies in recent JWST observations. Our tentative models and results c
 all for future studies with improved modelling of the interactions between
  PBHs\, particle DM\, and baryons to better understand the effects of PBHs
  on early structure/star formation and their imprints in high-redshift obs
 ervations. \n
LOCATION:Ryle seminar room + online
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