H2Cooling and Gravitational Collapse of Supersonically Induced Gas Objects

Yurina Nakazato, Gen Chiaki, Naoki Yoshida, Smadar Naoz, William Lake, Yeou S. Chiou

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


We study the formation and gravitational collapse of supersonically induced gas objects (SIGOs) in the early universe. We run cosmological hydrodynamics simulations of SIGOs, including relative streaming motions between baryons and dark matter. Our simulations also follow nonequilibrium chemistry and molecular hydrogen cooling in primordial gas clouds. A number of SIGOs are formed in the run with fast-streaming motions of 2 times the rms of the cosmological velocity fluctuations. We identify a particular gas cloud that condensates by H2 cooling without being hosted by a dark matter halo. The SIGO remains outside the virial radius of its closest halo, and it becomes Jeans unstable when the central gas-particle density reaches ∼100 cm-3 with a temperature of ∼200 K. The corresponding Jeans mass is ∼105 M, and thus the formation of primordial stars or a star cluster is expected in the SIGO.

Original languageEnglish
Article numberL12
JournalAstrophysical Journal Letters
Issue number1
Publication statusPublished - 2022 Mar 1

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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