We have observed nineteen quiescent Virgo cluster late-type spiral galaxies using the Long Wavelength Spectrometer (LWS) onboard ESAs' Infrared Space Observatory (ISO), detecting the C II 157.741 μm fine structure emission line in fourteen of them. Any influence of the Virgo cluster environment on the C II 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 C II ns-to-far-IR (FIR) ratio is less than in other surveys, there is a good correlation between the strength of the C II line and the IRAS-measured FIR flux. We find a trend of increasing C II ns-to-FIR flux ratio with increasing galaxy lateness. Moreover, the C II ns-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 C II emission and the massive star formation activity of the galaxy.
ISO Beyond the Peaks: The 2nd ISO Workshop on Analytical Spectroscopy
- Pub Date:
- November 2000