Emission from dust in galaxies: Metallicity dependence

H. Hirashita*, A. K. Inoue, H. Kamaya, H. Shibai

*この研究の対応する著者

研究成果: Article査読

22 被引用数 (Scopus)

抄録

Infrared (IR) dust emission from galaxies is frequently used as an indicator of star formation rate (SFR). However, the effect of the dust-to-gas ratio (i.e., amount of the dust) on the conversion law from IR luminosity to SFR has not so far been considered. Then, in this paper, we present a convenient analytical formula including this effect. In order to obtain the dependence on the dust-to-gas ratio, we extend the formula derived in our previous paper, in which a theoretical formula converting IR luminosity to SFR was derived. That formula was expressed as SFR/(M⊙ yr-1) = {3.3 10-10(1 - η)/(0.4 - 0.2f + 0.6ε)}(LIR/L⊙), where f is the fraction of ionizing photons absorbed by hydrogen, ε is the efficiency of dust absorption for nonionizing photons, η is the cirrus fraction of observed dust luminosity, and LIR is the observed luminosity of dust emission in the 8-1000-μm range. Our formula explains the IR excess of the Galaxy and the Large Magellanic Cloud. In the current paper, especially, we present the metallicity dependence of our conversion law between SFR and LIR. This is possible since both f and ε can be estimated via the dust-to-gas ratio, which is related to metallicity. We have confirmed that the relation between the metallicity and the dust-to-gas ratio is applied to both giant and dwarf galaxies. Finally, we apply the result to the cosmic star formation history. We find that the comoving SFR at z ∼ 3 calculated from previous empirical formulae is underestimated by a factor of 4-5.

本文言語English
ページ(範囲)83-90
ページ数8
ジャーナルAstronomy and Astrophysics
366
1
DOI
出版ステータスPublished - 2001
外部発表はい

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

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