The AMIGA sample of isolated galaxies III. IRAS data and infrared diagnostics

Abstract

We describe the mid- (MIR) and far- (FIR) infrared properties of a large ($\sim$1000) sample of the most isolated galaxies in the local Universe. This sample is intended as a ``nurture-free'' zero point against which more environmentally influenced samples can be compared. We reprocess IRAS MIR/FIR survey data using the ADDSCAN/SCANPI utility for 1030 out of 1050 galaxies from the Catalogue of Isolated Galaxies (CIG) as part of the AMIGA project. We focus on diagnostics (FIR luminosity $L_{FIR}$, $R=\log(L_{FIR}/L_{B})$ and IRAS colours) thought to be sensitive to effects of environment or interaction. The distribution of $\log(L_{FIR})$ is sharply peaked from 9.0--10.5 with very few ($