The emission by dust and stars of nearby galaxies in the Herschel KINGFISH survey

Ramin A. Skibba, Charles W. Engelbracht, Daniel Dale, Joannah Hinz, Stefano Zibetti, Alison Crocker, Brent Groves, Leslie Hunt, Benjamin D. Johnson, Sharon Meidt, Eric Murphy, Philip Appleton, Lee Armus, Alberto Bolatto, Bernhard Brandl, Daniela Calzetti, Kevin Croxall, Maud Galametz, Karld Gordon, Robert C. KennicuttJin Koda, Oliver Krause, Edward Montiel, Hans Walter Rix, Hélène Roussel, Karin Sandstrom, Marc Sauvage, Eva Schinnerer, J. D. Smith, Fabian Walter, Christined Wilson, Mark Wolfire

Research output: Contribution to journalArticlepeer-review

133 Scopus citations

Abstract

Using new far-infrared imaging from the Herschel Space Observatory with ancillary data from ultraviolet (UV) to submillimeter wavelengths, we estimate the total emission from dust and stars of 62 nearby galaxies in the KINGFISH survey in a way that is as empirical and model independent as possible. We collect and exploit these data in order to measure from the spectral energy distributions (SEDs) precisely how much stellar radiation is intercepted and re-radiated by dust, and how this quantity varies with galaxy properties. By including SPIRE data, we are more sensitive to emission from cold dust grains than previous analyses at shorter wavelengths, allowing for more accurate estimates of dust temperatures and masses. The dust/stellar flux ratio, which we measure by integrating the SEDs, has a range of nearly three decades (from 10-2.2 to 100.5). The inclusion of SPIRE data shows that estimates based on data not reaching these far-IR wavelengths are biased low by 17% on average. We find that the dust/stellar flux ratio varies with morphology and total infrared (IR) luminosity, with dwarf galaxies having faint luminosities, spirals having relatively high dust/stellar ratios and IR luminosities, and some early types having low dust/stellar ratios. We also find that dust/stellar flux ratios are related to gas-phase metallicity ( and -0.22 0.12 for metal-poor and intermediate-metallicity galaxies, respectively), while the dust/stellar mass ratios are less so (differing by 0.2 dex); the more metal-rich galaxies span a much wider range of the flux ratios. In addition, the substantial scatter between dust/stellar flux and dust/stellar mass indicates that the former is a poor proxy of the latter. Comparing the dust/stellar flux ratios and dust temperatures, we also show that early types tend to have slightly warmer temperatures (by up to 5 K) than spiral galaxies, which may be due to more intense interstellar radiation fields, or possibly to different dust grain compositions. Finally, we show that early types and early-type spirals have a strong correlation between the dust/stellar flux ratio and specific star formation rate, which suggests that the relatively bright far-IR emission of some of these galaxies is due to ongoing (if limited) star formation as well as to the radiation field from older stars, which is heating the dust grains.

Original languageEnglish (US)
Article number89
JournalAstrophysical Journal
Volume738
Issue number1
DOIs
StatePublished - Sep 1 2011
Externally publishedYes

Keywords

  • dust, extinction
  • galaxies: ISM
  • galaxies: evolution
  • galaxies: general
  • galaxies: photometry
  • infrared: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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