C ii] 158-μm observations of a sample of late-type galaxies from the Virgo cluster

Abstract

We have observed 19 quiescent Virgo cluster spiral galaxies with the Long Wavelength Spectrometer (LWS) onboard ESAs’ Infrared Space Observatory (ISO), detecting 14 in the [Cii] 157.741 μm fine structure line. Any in.uence of the Virgo cluster environment on the [Cii] emission was found to be small compared with the strong dependence of the line emission on basic measurables such as morphology or bulk mass of the stellar component, as measured by the Near-IR (K’-band) luminosity. While the range of the [Cii]-to-far-IR ratio is less than in other surveys, there is a good correlation between the strength of the [Cii] line and the far-IR flux, as measured by IRAS. We find a trend of increasing [Cii]-to-FIR flux ratio with increasing galaxy lateness. Moreover, the [Cii]-to-K’-band flux ratio shows a two order of magnitude difference between RC3 type 0 and RC3 types later than 5. These two correlations express the relation between the mechanism of the [Cii] emission and the massive star formation activity of the galaxy.