Formation of globular cluster candidates in merging proto-galaxies at high redshift: a view from the FIRE cosmological simulations

Journal Article · Thu Nov 23 00:00:00 EST 2017 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stx2994· OSTI ID:1423127

Kim, Ji-hoon ^[1]; Ma, Xiangcheng ^[2]; Grudić, Michael Y. ^[2]; Hopkins, Philip F. ^[2]; Hayward, Christopher C. ^[3]; Wetzel, Andrew ^[4]; Faucher-Giguère, Claude-André ^[5]; Kereš, Dušan ^[6]; Garrison-Kimmel, Shea ^[2]; Murray, Norman ^[7]

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1. SLAC National Accelerator Lab., Menlo Park, CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology; Stanford Univ., CA (United States). Dept. of Physics; California Inst. of Technology (CalTech), Pasadena, CA (United States). TAPIR, Dept. of Astronomy
2. California Inst. of Technology (CalTech), Pasadena, CA (United States). TAPIR, Dept. of Astronomy
3. Center for Computational Astrophysics, New York, NY (United States). Flatiron Inst.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
4. California Inst. of Technology (CalTech), Pasadena, CA (United States). TAPIR, Dept. of Astronomy; Carnegie Observatories, Pasadena, CA (United States); Univ. of California, Davis, CA (United States). Dept. of Physics
5. Northwestern Univ., Evanston, IL (United States). Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Dept. of Physics and Astronomy
6. Univ. of California, San Diego, CA (United States). Center for Astrophysics and Space Sciences, Dept. of Physics
7. Univ. of Toronto, ON (Canada). Canadian Inst. for Theoretical Astrophysics

Using a state-of-the-art cosmological simulation of merging proto-galaxies at high redshift from the FIRE project, with explicit treatments of star formation and stellar feedback in the interstellar medium, we investigate the formation of star clusters and examine one of the formation hypotheses of present-day metal-poor globular clusters. Here, we find that frequent mergers in high-redshift proto-galaxies could provide a fertile environment to produce long-lasting bound star clusters. The violent merger event disturbs the gravitational potential and pushes a large gas mass of ≳ 10^5–6 M_⊙ collectively to high density, at which point it rapidly turns into stars before stellar feedback can stop star formation. The high dynamic range of the reported simulation is critical in realizing such dense star-forming clouds with a small dynamical time-scale, tff ≲ 3 Myr, shorter than most stellar feedback time-scales. Our simulation then allows us to trace how clusters could become virialized and tightly bound to survive for up to ~420 Myr till the end of the simulation. Finally, because the cluster's tightly bound core was formed in one short burst, and the nearby older stars originally grouped with the cluster tend to be preferentially removed, at the end of the simulation the cluster has a small age spread.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: Alfred P. Sloan Foundation; Gordon and Betty Moore Foundation; National Aeronautic and Space Administration (NASA); National Science Foundation (NSF); USDOE
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1423127
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 3 Vol. 474; ISSN 0035-8711
• Publisher: Royal Astronomical Society
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
cosmology theory
galaxies star clusters general
galaxies formation
galaxies kinematics and dynamics
globular clusters general
stars formation