EDP Sciences
Free Access
Volume 417, Number 1, April I 2004
Page(s) 39 - 50
Section Extragalactic astronomy
DOI https://doi.org/10.1051/0004-6361:20035602
Published online 16 March 2004

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

Dust masses and star formation in bright IRAS galaxies

Application of a physical model for the interpretation of FIR observations
A. Misiriotis1, I. E. Papadakis1, 2, N. D. Kylafis1, 2 and J. Papamastorakis1, 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 )

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

© ESO 2004

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.