Predicting dust extinction from the stellar mass of a galaxy

Timothy Garn, Philip N. Best

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate how the typical dust extinction of Ha luminosity from a star-forming galaxy depends upon star formation rate (SFR), metallicity and stellar mass independently, using a sample of similar to 90 000 galaxies from Data Release 7 of the Sloan Digital Sky Survey (SDSS). We measure extinctions directly from the Balmer decrement of each source, and while higher values of extinction are associated with an increase in any of the three parameters, we demonstrate that the fundamental property that governs extinction is stellar mass. After this mass-dependent relationship is removed, there is very little systematic dependence of the residual extinctions with either SFR or metallicity, and no significant improvement is obtained from a more general parametrization. In contrast to this, if either an SFR-dependent or a metallicity-dependent extinction relationship is applied, the residual extinctions show significant trends that correlate with the other parameters. Using the SDSS data, we present a relationship to predict the median dust extinction of a sample of galaxies from its stellar mass, which has a scatter of similar to 0.3 mag. The relationship was calibrated for Ha emission, but can be more generally applied to radiation emitted at other wavelengths. These results have important applications for studies of high-redshift galaxies, where individual extinction measurements are hard to obtain but stellar mass estimates can be relatively easily estimated from long-wavelength data.

Original languageEnglish
Pages (from-to)421-432
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume409
Issue number1
DOIs
Publication statusPublished - 21 Nov 2010

Keywords

  • dust, extinction
  • galaxies: evolution
  • galaxies: high-redshift
  • galaxies: ISM
  • DIGITAL-SKY-SURVEY
  • STAR-FORMATION RATE
  • ACTIVE GALACTIC NUCLEI
  • METALLICITY RELATION
  • FORMING GALAXIES
  • FORMATION RATES
  • HIGH-REDSHIFT
  • ORIGIN
  • LUMINOSITY
  • DEPENDENCE

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