Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

We studied the global characteristics of dust emission in a large sample of emission-line star-forming galaxies. The sample consists of two subsamples. One subsample (SDSS sample) includes ~4000 compact star-forming galaxies from the Sloan Digital Sky Survey (SDSS), which were also detected in all four bands at 3.4 μm, 4.6 μm, 12 μm, and 22 μm of the WISE all-sky survey. The second subsample (Herschel sample) is a sample of 28 compact star-forming galaxies observed with Herschel in the FIR range. Data of the Herschel sample were supplemented by the photometric data from the Spitzer observations, GALaxy Evolution Explorer (GALEX) survey, SDSS, Wide-Field Infrared Survey Explorer (WISE), Two Micron All Sky Survey (2MASS), NRAO VLA Sky Survey (NVSS), and Faint Images of the Radio Sky at Twenty-cm (FIRST) survey, as well as optical and Spitzer spectra and data in submm and radio ranges. It is found that warm dust luminosities of galaxies from the SDSS sample and cold and warm dust luminosities of galaxies from the Herschel sample are strongly correlated with Hβ luminosities, which implies that one of the main sources of dust heating in star-forming galaxies is ionising UV radiation of young stars. Likely, a significant fraction of dust is located inside H i