• DOI:10.1086/308692
• Corpus ID: 10701579

The Dust Content and Opacity of Actively Star-Forming Galaxies

@article{Calzetti1999TheDC,
  title={The Dust Content and Opacity of Actively Star-Forming Galaxies},
  author={Daniela Calzetti and Lee Armus and Ralph C. Bohlin and Anne L. Kinney and Janne M. Koornneef and Thaisa Storchi-Bergmann},
  journal={The Astrophysical Journal},
  year={1999},
  volume={533},
  pages={682-695}
}

• D. Calzetti, L. Armus, +3 authors T. Storchi-Bergmann
• Published 24 November 1999
• Physics
• The Astrophysical Journal

We present far-infrared (FIR) photometry at 150 and 205 km of eight low-redshift starburst galaxies obtained with the Infrared Space Observatory (ISO) ISOPHOT. Five of the eight galaxies are detected in both wave bands, and these data are used, in conjunction with IRAS archival photometry, to model the dust emission at km. The FIR spectral energy distributions (SEDs) are best —tted by a com- j Z 40 bination of two modi—ed Planck functions, with T D 40¨55 K (warm dust) and T D 20¨23 K (cool dust) and with a dust emissivity index v \ 2. The cool dust can be a major contributor to the FIR emission of starburst galaxies, representing up to 60% of the total —ux. This component is heated not only by the general interstellar radiation —eld, but also by the starburst itself. The cool dust mass is up to D150 times larger than the warm dust mass, bringing the gas-to-dust ratios of the starbursts in our sample close to Milky Way values, once rescaled for the appropriate metallicity. The ratio between the total dust FIR emission in the range 1¨1000 km and the IRAS FIR emission in the range 40¨120 k mi s D1.75, with small variations from galaxy to galaxy. This ratio is about 40% larger than previously inferred from data at millimeter wavelengths. Although the galaxies in our sample are generally classi—ed as ii UV bright,ˇˇ for four of them the UV energy emerging shortward of 0.2 km is less than 15% of the FIR energy. On average, about 30% of the bolometric —ux is coming out in the UVtonear-IR wave- length range; the rest is emitted in the FIR. Energy balance calculations show that the FIR emission predicted by the dust reddening of the UVtonear-IR stellar emission is within a factor of D 2o f the observed value in individual galaxies and within 20% when averaged over a large sample. If our sample of local starbursts is representative of high-redshift UV-bright, star-forming galaxies, these gal- (z Z 1), axiesFIR emission will be generally undetected in submillimeter surveys, unless (1) their bolometric luminosity is comparable to or larger than that of ultraluminous FIR galaxies and (2) their FIR SED contains a cool dust component. Subject headings: galaxies: starburstinfrared: galaxiesinfrared: ISM: continuum ¨ ISM: dust, extinction