Issue |
A&A
Volume 410, Number 1, October IV 2003
|
|
---|---|---|
Page(s) | 83 - 100 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20031144 | |
Published online | 17 November 2003 |
Star formation rate in galaxies from UV, IR, and Hα estimators *
1
Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi, 5, 50125 Firenze, Italy e-mail: hirashita@u.phys.nagoya-u.ac.jp
2
Laboratoire d'Astrophysique de Marseille, BP 8, 13376 Marseille Cedex 12, France e-mail: veronique.buat@astrsp-mrs.fr
3
Department of Astronomy, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan e-mail: akinoue@scphys.kyoto-u.ac.jp
Corresponding author: H. Hirashita, hirashita@u.phys.nagoya-u.ac.jp
Received:
18
March
2003
Accepted:
11
July
2003
Infrared (IR) luminosity of galaxies originating from dust
thermal emission can be used as an indicator of the star
formation rate (SFR). Inoue et al. ([CITE], IHK) have
derived a formula for the conversion from dust IR luminosity to
SFR by using the following three quantities: the fraction of
Lyman continuum luminosity absorbed by gas (f), the fraction
of UV luminosity absorbed by dust (ϵ), and the
fraction of dust heating from old (108 yr) stellar
populations (η). We develop a method to estimate those
three quantities based on the idea that the various way of SFR
estimates from ultraviolet (UV) luminosity (2000 Å
luminosity), Hα luminosity, and dust IR luminosity
should return the same SFR. After applying our method to
samples of galaxies, the following results are obtained in our
framework. First, our method is applied to a sample of
star-forming galaxies, finding that
,
, and
as representative
values. Next, we apply the method to a starburst sample, which
shows larger extinction than the star-forming galaxy sample.
With the aid of f, ϵ, and η, we are able to
estimate reliable SFRs from UV and/or IR luminosities.
Moreover, the Hα luminosity, if the Hα extinction
is corrected by using the Balmer decrement, is suitable for a
statistical analysis of SFR, because the same correction
factor for the
Lyman continuum extinction (i.e.
) is applicable to both
normal and starburst galaxies over all the range of SFR.
The metallicity dependence of f and ϵ is also tested:
Only the latter proves to have
a correlation with metallicity. As an extension of
our result, the local (
) comoving density of SFR can be
estimated with our dust extinction corrections. We show that all
UV, Hα, and IR comoving luminosity densities at
give
a consistent SFR per comoving volume
(~
). Useful formulae for SFR
estimate are listed.
Key words: ISM: dust, extinction / galaxies: evolution / galaxies: ISM / galaxies: starburst / infrared: galaxies / ultraviolet: galaxies
© ESO, 2003
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