---
res:
  bibo_abstract:
  - Approximately 200 supermassive black holes (SMBHs) have been discovered within
    the first ∼gigayear after the Big Bang. One pathway for the formation of SMBHs
    is through the collapse of supermassive stars (SMSs). A possible obstacle to this
    scenario is that the collapsing gas fragments and forms a cluster of main-sequence
    stars. Here, we raise the possibility that stellar collisions may be sufficiently
    frequent and energetic to inhibit the contraction of the massive protostar, avoiding
    strong UV radiation driven outflows, and allowing it to continue growing into
    an SMS. We investigate this scenario with semianalytic models incorporating star
    formation; gas accretion; dynamical friction from stars and gas; stellar collisions;
    and gas ejection. We find that when the collapsing gas fragments at a density
    of ≲3 × 1010 cm−3, the central protostar contracts due to infrequent stellar mergers,
    and in turn photoevaporates the remaining collapsing gas, resulting in the formation
    of a ≲104 M⊙ object. On the other hand, when the collapsing gas fragments at higher
    densities (expected for a metal-poor cloud with Z ≲ 10−5 Z⊙ with suppressed H2
    abundance) the central protostar avoids contraction and keeps growing via frequent
    stellar mergers, reaching masses as high as ∼105–106 M⊙. We conclude that frequent
    stellar mergers represent a possible pathway to form massive BHs in the early
    universe.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Hiromichi
      foaf_name: Tagawa, Hiromichi
      foaf_surname: Tagawa
  - foaf_Person:
      foaf_givenName: Zoltán
      foaf_name: Haiman, Zoltán
      foaf_surname: Haiman
      foaf_workInfoHomepage: http://www.librecat.org/personId=7c006e8c-cc0d-11ee-8322-cb904ef76f36
  - foaf_Person:
      foaf_givenName: Bence
      foaf_name: Kocsis, Bence
      foaf_surname: Kocsis
  bibo_doi: 10.3847/1538-4357/ab7922
  bibo_issue: '1'
  bibo_volume: 892
  dct_date: 2020^xs_gYear
  dct_isPartOf:
  - http://id.crossref.org/issn/0004-637X
  - http://id.crossref.org/issn/1538-4357
  dct_language: eng
  dct_publisher: American Astronomical Society@
  dct_title: Making a supermassive star by stellar bombardment@
...