Star Formation and Dust Extinction Properties of Local Galaxies as seen from AKARI and GALEX

TL;DR

This study combines UV and IR data from AKARI and GALEX to accurately estimate star formation rates and dust extinction in local galaxies, revealing that dust heavily obscures star formation, especially in highly active galaxies.

Contribution

It provides a more precise analysis of star formation and dust extinction in local galaxies using larger datasets from AKARI and GALEX surveys, improving upon previous studies.

Findings

Most star formation luminosity is dominated by dust emission.

Galaxies with SFR >20 M_sun/yr have nearly all star formation obscured by dust.

Larger sample size leads to higher precision in results.

Abstract

An accurate estimation of the star formation-related properties of galaxies is crucial for understanding the evolution of galaxies. In galaxies, ultraviolet (UV) light emitted by recently formed massive stars is attenuated by dust, which is also produced by star formation (SF) activity, and is reemitted at mid- and far- infrared (IR) wavelengths. In this study, we investigate the star formation rate (SFR) and dust extinction using UV and IR data. We selected local galaxies which are detected at AKARI FIS 90 um and matched the IRAS IIFSCz 60 um select catalog. We measured FUV and NUV flux densities from GALEX images. We examined the SF and extinction of Local galaxies using four bands of AKARI. Then, we calculated FUV and total IR luminosities, and obtained the SF luminosity, L_{SF}, the total luminosity related to star formation activity, and the SFR. We find that in most galaxies, L_{SF} is dominated by L_{dust}. We also find that galaxies with higher SF activity have a higher fraction of their SF hidden by dust. In fact, the SF of galaxies with SFRs >20 M_{sun}/yr is almost completely hidden by dust. Our results boast a significantly higher precision with respect to previously published works, due to the use of much larger object samples from the AKARI and GALEX all sky surveys.