ISO Observations of Star-Forming Galaxies

Abstract.

The Infrared Space Observatory (ISO) is used to carry out mid-IR (7 and $15 \mu$m) and far-IR ($90 \mu$m) observations of a sample of star-forming sub-mJy radio sources. By selecting the sample at radio wavelengths, one avoids biases due to dust obscuration. It is found that the mid-IR luminosities, covering the PAH features, measure the star formation rate for galaxies with P _1.4GHz < 10²³ W Hz^-1. This is further confirmed using the H$\alpha$ luminosities. The far-IR emission is also found to trace the SFR over the whole range of radio and H$\alpha$ luminosities. The implication of the mid-IR measurements in estimating the SFRs from the future infrared space missions (SIRTF and ASTRO-F) is discussed.