Spitzer Observations of Cold Dust Galaxies

TL;DR

This study combines Spitzer and SCUBA observations to analyze cold dust in 11 galaxies, revealing its widespread presence and significant contribution to galaxy luminosity, and providing new templates for interpreting galaxy dust properties.

Contribution

It introduces combined mid- and far-infrared data to improve dust temperature and mass measurements, expanding the parameter space for galaxy dust models.

Findings

Cold dust is present in all spiral galaxy types.

Galaxies with cold dust have flatter far-IR slopes.

New data extend the templates for galaxy dust properties.

Abstract

We combine new Spitzer Space Telescope observations in the mid- and far-infrared with SCUBA 850 micron observations to improve the measurement of dust temperatures, masses and luminosities for 11 galaxies of the SCUBA Local Universe Galaxy Survey (SLUGS). By fitting dust models we measure typical dust masses of 10E7.9 M_sol and dust luminosities of ~ 10E10 L_sol, for galaxies with modest star formation rates. The data presented in this paper combined with previous observations show that cold dust is present in all types of spiral galaxies and is a major contributor to their total luminosity. Because of the lower dust temperature of the SCUBA sources measured in this paper, they have flatter Far-IR nu F_nu(160um)/nu F_nu(850um) slopes than the larger Spitzer Nearby Galaxies Survey (SINGS), the sample that provides the best measurements of the dust properties of galaxies in the nearby universe. The new data presented here added to SINGS extend the parameter space that is well covered by local galaxies, providing a comprehensive set of templates that can be used to interpret the observations of nearby and distant galaxies.