Growth of First Galaxies: Impacts of Star Formation and Stellar Feedback

Journal Article · Fri Sep 01 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA82B5· OSTI ID:22875870

Yajima, Hidenobu ^[1]; Nagamine, Kentaro ^[2]; Zhu, Qirong ^[3]; Khochfar, Sadegh ^[4]

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1. Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578 (Japan)
2. Theoretical Astrophysics, Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)
3. Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
4. Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom)

Recent observations have detected galaxies at high-redshift z∼6--11, and revealed the diversity of their physical properties, from normal star-forming galaxies to starburst galaxies. To understand the properties of these observed galaxies, it is crucial to understand the star formation (SF) history of high-redshift galaxies under the influence of stellar feedback. In this work, we present the results of cosmological hydrodynamic simulations with zoom-in initial conditions, and investigate the formation of the first galaxies and their evolution toward observable galaxies at z∼6. We focus on three different galaxies that end up in halos with masses M{sub h}=2.4×10{sup 10} h{sup −1} M{sub ⊙} (Halo-10), 1.6×10{sup 11} h{sup −1} M{sub ⊙} (Halo-11), and 0.7×10{sup 12} h{sup −1} M{sub ⊙} (Halo-12) at z = 6. Our simulations also probe the impacts of different subgrid assumptions, i.e., SF efficiency and cosmic reionization, on SF histories in the first galaxies. We find that SF occurs intermittently due to supernova (SN) feedback at z≳10, and then it proceeds more smoothly as the halo mass grows at lower redshifts. Galactic disks are destroyed due to SN feedback, while galaxies in simulations with no feedback or lower SF efficiency models can sustain a galactic disk for long periods ≳10 Myr. The expulsion of gas at the galactic center also affects the inner dark matter density profile for a short period. Our simulated galaxies in Halo-11 and Halo-12 reproduce the SF rates and stellar masses of observed Lyα emitters at z∼7--8 fairly well given the observational uncertainties.

• OSTI ID: 22875870
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 846; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPUTERIZED SIMULATION
DENSITY
GALACTIC EVOLUTION
GALAXIES
HYDRODYNAMICS
MASS
NONLUMINOUS MATTER
RED SHIFT
STAR EVOLUTION