Spectral energy distributions of an AKARI-SDSS-GALEX sample of galaxies

摘要

Context. The nearby universe remains the best laboratory to understand the physical properties of galaxies and is a reference for any comparison with high redshift observations. The all sky (or very large) surveys that have been performed from the ultraviolet (UV) to the far-infrared (far-IR) provide us with large datasets of very large wavelength coverage to perform a reference study. Aims. We investigate the dust attenuation characteristics, as well as the star formation rate (SFR) calibrations of a sample of nearby galaxies observed over 13 bands from 0.15 to 160 μm. Methods. A sample of 363 galaxies is built from the AKARI /FIS all sky survey cross-correlated with the SDSS and GALEX surveys. Broad-band spectral energy distributions are fitted with the CIGALE code optimized to analyse variations in the dust attenuation curves and SFR measurements and based on an energetic budget between the stellar and dust emission. Results. Our galaxy sample is primarily selected in far-IR and mostly constituted of massive, actively star-forming galaxies. There is some evidence for a dust attenuation law that is slightly steeper than that used for starburst galaxies but we are unable to constrain the presence or not of a bump at 220 nm. We confirm that a time-dependent dust attenuation is necessary to perform the best fits. Various calibrations of the dust attenuation in the UV as a function of UV-optical colours are discussed. A calibration of the current SFR combining UV and total IR emissions is proposed with an accurate estimate of dust heating by old stars. For the whole sample, 17 of the total dust luminosity is unrelated to the recent star formation.