TY - JOUR
T1 - Formation of globular cluster candidates in merging proto-galaxies at high redshift
T2 - A view from the FIRE cosmological simulations
AU - Kim, Ji Hoon
AU - Ma, Xiangcheng
AU - Grudić, Michael Y.
AU - Hopkins, Philip F.
AU - Hayward, Christopher C.
AU - Wetzel, Andrew
AU - Faucher-Giguère, Claude André
AU - Kereš, Dušan
AU - Garrison-Kimmel, Shea
AU - Murray, Norman
N1 - Funding Information:
The authors thank Tom Abel, Nathan Bastian, Diederik Kruijssen, Joel Primack, and Eros Vanzella for useful discussions and insightful comments during the progress of this study. Ji-hoon Kim acknowledges support from NASA through an Einstein Postdoctoral Fellowship grant PF4-150147 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060. He also acknowledges support from the Moore Center for Theoretical Cosmology and Physics at Caltech. He thanks for the support from the computational team at SLAC National Accelerator Laboratory, from Shawfeng Dong at the University of California Santa Cruz, and from Chris Mach at Caltech during the usage of the clusters for simulation analyses. The computing time used for the presented simulations was provided by Extreme Science and Engineering Discovery Environment (XSEDE) allocations TG-AST120025, TG-AST130039, TG-AST140023, and TG-AST140064. XSEDE is supported by the National Science Foundation (NSF) grant ACI-1053575. Philip Hopkins acknowledges support by the Gordon and Betty Moore Foundation through grant 776 to the Caltech Moore Center for Theoretical Cosmology and Physics, by the Alfred P. Sloan Foundation through Sloan Research Fellowship BR2014-022, by the NSF through grant AST-1411920 and CAREER grant 1455342, and by NASA through the ATP grant NNX14AH35G. The Flatiron Institute is supported by the Simons Foundation. Andrew Wetzel acknowledges support by a Caltech-Carnegie Fellowship, in part through the Moore Center for Theoretical Cosmology and Physics at Caltech, and by NASA through grant HST-GO-14734 from STScI. Claude-André Faucher-Giguère acknowledges support by the NSF through grants AST-1412836 and AST-1517491, by NASA through grant NNX15AB22G, and by STScI through grants HST-AR-14293.001-A and HST-GO-14268.022-A. Dusˇan Keresˇ acknowledges support by the NSF through grant AST-1412153, and by the Cottrell Scholar Award from the Research Corporation for Science Advancement. Shea Garrison-Kimmel acknowledges support from NASA through an Einstein Postdoctoral Fellowship grant PF5-160136. The publicly available YT code used in the analysis of this work is the product of collaborative efforts by many independent scientists from numerous institutions around the world. Their commitment to open science has helped make this work possible.
PY - 2018/3/1
Y1 - 2018/3/1
N2 - 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. 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 ≳ 105-6M⊙ 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. 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.
AB - 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. 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 ≳ 105-6M⊙ 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. 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.
KW - Cosmology: theory
KW - Galaxies: formation
KW - Galaxies: kinematics and dynamics
KW - Galaxies: star clusters: general
KW - Globular clusters: general
KW - Stars: formation
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U2 - 10.1093/mnras/stx2994
DO - 10.1093/mnras/stx2994
M3 - Article
AN - SCOPUS:85040236187
VL - 474
SP - 4232
EP - 4244
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -