Blue compact dwarf galaxies with spitzer: The infrared/radio properties

We study the correlation between the radio, mid-infrared, and far-infrared properties for a sample of 28 blue compact dwarf (BCD) and low-metallicity star-forming galaxies observed by Spitzer. We find that these sources extend the same far-infraredYtoYradio correlation typical of star-forming late-type galaxies to lower luminosities. In BCDs, the 24 mu m (or 22 mu m) mid-infrared-to-radio correlation is similar to that of starburst galaxies, although there is somewhat larger dispersion in their q(24) parameter compared to their q(FIR). No strong correlations between the q parameter and galaxy metallicity or effective dust temperature have been detected, although there is a hint of decreasing q(24) at low metallicities. The two lowest metallicity dwarfs in our sample, IZw 18 and SBS 0335-052E, despite their similar chemical abundance, deviate from the average q(24) ratio in opposite manners, displaying an apparent radio excess and dust excess, respectively.