Cold dust in late-type Virgo Cluster galaxies

Abstract

We have statistically analyzed the spatially integrated far-infrared (FIR) emissions of the complete volume- and luminosity-limited sample of late-type (later than S0) Virgo cluster galaxies measured using the Infrared Space Observatory (ISO) by Tuffs et al. (2002) in bands centered on 60, 100 and 170 microns. 30 out of 38 galaxies detected at all three wavelengths contain a cold dust emission component, present within all morphological types of late-type systems ranging from early giant spirals to Blue Compact Dwarfs (BCDs), and which could not have been recognized by IRAS. The temperatures of the cold dust were found to be broadly distributed, with a median of 18 K, some 8-10 K lower than would have been predicted from IRAS. The derived total dust masses are correspondingly increased by factors of typically 6 - 13. A particularly significant result concerns the low dust temperatures (ranging down to less than 10 K) and large dust masses associated with the Im and BCD galaxies in our sample. We propose two scenarios to account for the FIR characteristics of these systems.