Metal enrichment in supernova-dominated high-z galaxies

Masao Mori, Masayuki Umemura, Hidenobu Yajima

研究成果: Conference contribution


We simulate the dynamical and chemical evolution of a forming galaxy embedded in a dark matter halo, using a three-dimensional N-body / hydrodynamic simulation code combined with stellar population synthesis. We find that a sparkling phase with multitudinous SN explosions at less than 3×10 8 years exhibits intense Lyman aemission from cooling shocks and well resembles Lyman a emitters (LAEs) that have been discovered at redshifts greater than three. Subsequently, the galaxy shifts to a stellar continuum radiation-dominated phase within 109 years, which appears like Lyman break galaxies (LBGs). At the LAE phase the abundance of heavy elements is subsolar and shows strong spatial variance, but it convergently reaches a level of solar abundance at the LBG phase. Hence, it turns out that LAEs and LBGs are the on-going and major phases of chemical enrichment in a galaxy. Moreover, in order to assess the contribution of LBGs and LAEs at redshifts 3 < z < 7 to the ionization of intergalactic medium (IGM), we investigate the escape fractions of ionizing photons from supernova-dominated galaxies by solving the three-dimensional radiative transfer. According to the chemical enrichment, we incorporate the effect of dust extinction. As a result, it is found that, in contrast to the previous theoretical predictions, a larger fraction of ionizing photons can escape from primordial galaxies. The resultant escape fractions are as large as 46% at z = 7 to 17% at z = 3.7, which nicely match the recent estimations derived from the flux ratio at 1500 Åto 900 Åof LAEs and LBGs.

ホスト出版物のタイトルDeciphering the Ancient Universe with Gamma-Ray Bursts
出版ステータスPublished - 2010
イベントInternational Symposium "Deciphering the Ancient Universe with Gamma-Ray Bursts" - Kyoto, Japan
継続期間: 2010 4月 192010 4月 23


名前AIP Conference Proceedings


OtherInternational Symposium "Deciphering the Ancient Universe with Gamma-Ray Bursts"

ASJC Scopus subject areas

  • 物理学および天文学(全般)


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