Dust masses and star formation in bright IRAS galaxies

Free access article

Issue		A&A Volume 417, Number 1, April I 2004


Page(s)		39 - 50
Section		Extragalactic astronomy
DOI		http://dx.doi.org/10.1051/0004-6361:20035602

A&A 417, 39-50 (2004)
DOI: 10.1051/0004-6361:20035602

Application of a physical model for the interpretation of FIR observations

A. Misiriotis¹, I. E. Papadakis^{1, 2}, N. D. Kylafis^{1, 2} and J. Papamastorakis^{1, 2}

¹ University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
² Foundation for Research and Technology-Hellas, PO Box 1527, 711 10 Heraklion, Crete, Greece

(Received 30 October 2003 / Accepted 3 December 2003 )

Abstract
We address the problem of modeling the far-infrared (FIR) spectrum and deriving the star-formation rate (SFR) and the dust mass of spiral galaxies. We use the realistic physical model of Popescu et al. ([CITE]) to describe the overall ultra-violet (UV), optical and FIR spectral energy distribution (SED) of a spiral galaxy. The model takes into account the 3-dimensional old and young stellar distributions in the bulge and the disk of a galaxy, together with the dust geometry. The geometrical characteristics of the galaxy and the intrinsic optical and near-infrared spectra are determined by the galaxy's observed K-band photometry. The UV part of the spectrum is assumed to be proportional to the SFR through the use of population synthesis models. By solving the radiative transfer equation, we are able to determine the absorbed energy, the dust temperature and the resulting FIR spectrum. The model has only three free parameters: SFR, dust mass, and the fraction of the UV radiation which is absorbed locally by dense dust in the HII regions. Using this model, we are able to fit well the FIR spectra of 62 bright IRAS galaxies from the "SCUBA Local Universe Galaxy Survey" of Dunne et al. ([CITE]). As a result, we are able to determine, among others, their SFR and dust mass. We find that, on average, the SFR (in absolute units), the star-formation efficiency, the SFR surface density and the ratio of FIR luminosity over the total intrinsic luminosity, are larger than the respective values of typical spiral galaxies of the same morphological type. We also find that the mean gas-to-dust mass ratio is close to the Galactic value, while the average central face-on optical depth of these galaxies in the V band is 2.3. Finally, we find a strong correlation between SFR or dust mass and observed FIR quantities like total FIR luminosity or FIR luminosity at 100 and 850 $\mathrm{\mu m}$ . These correlations yield well-defined relations, which can be used to determine a spiral galaxy's SFR and dust-mass content from FIR observations.

Key words: dust, extinction -- galaxies: stellar content -- galaxies: ISM -- infrared: galaxies

Offprint request: A. Misiriotis, angmis@physics.uoc.gr

SIMBAD Objects

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.