THE ROLE OF DUST IN THE EARLY UNIVERSE. I. PROTOGALAXY EVOLUTION

Journal Article · Fri Jul 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/735/1/44· OSTI ID:21576548

Yamasawa, Daisuke; Habe, Asao; Kozasa, Takashi ^[1]; Nozawa, Takaya; Nomoto, Ken'ichi ^[2]; Hirashita, Hiroyuki ^[3]; Umeda, Hideyuki ^[4]

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1. Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan)
2. Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)
3. Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)
4. Department of Astronomy, School of Science, University of Tokyo, Hongo, Tokyo 113-0033 (Japan)

We develop one-zone galaxy formation models in the early universe, taking into account dust formation and evolution by supernova (SN) explosions. We focus on the time evolution of dust size distribution, because H{sub 2} formation on the dust surface plays a critical role in the star formation process in the early universe. In the model, we assume that star formation rate (SFR) is proportional to the total amount of H{sub 2}. We consistently treat (1) the formation and size evolution of dust, (2) the chemical reaction networks including H{sub 2} formation both on the surface of dust and in gas phase, and (3) the SFR in the model. First, we find that, because of dust destruction due to both reverse and forward shocks driven by SNe, H{sub 2} formation is more suppressed than in situations without such dust destruction. At the galaxy age of {approx}0.8 Gyr, for galaxy models with virial mass M{sub vir} = 10{sup 9} M{sub sun} and formation redshift z{sub vir} = 10, the molecular fraction is 2.5 orders of magnitude less in the model with dust destruction by both shocks than that in the model without dust destruction. Second, we show that the H{sub 2} formation rate strongly depends on the interstellar medium (ISM) density around SN progenitors. The SFR in higher ISM density is lower, since dust destruction by reverse shocks is more effective in higher ISM density. We conclude that not only the amount but also the size distribution of dust related to star formation activity strongly affects the evolution of galaxies in the early universe.

• OSTI ID: 21576548
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 735; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DISTRIBUTION
DUSTS
ELEMENTS
EVOLUTION
GALACTIC EVOLUTION
HYDROGEN
NONMETALS
PARTICLE SIZE
SIZE
STARS
UNIVERSE