Extinction Corrected Star Formation Rates Empirically Derived from Ultraviolet-Optical Colors

TL;DR

This paper develops an empirical method to correct ultraviolet-based star formation rates in galaxies using UV-optical colors, improving the accuracy of SFR estimates for blue sequence galaxies.

Contribution

It introduces a new empirical linear relation between UV-optical colors and the SFR to UV luminosity ratio, aiding dust attenuation correction in galaxy surveys.

Findings

The method accurately reconciles UV and emission line SFRs for blue galaxies.

It fails for red sequence and certain high-redshift galaxies.

The relation is simple and applicable to large galaxy samples.

Abstract

Using a sample of galaxies from the Sloan Digital Sky Survey spectroscopic catalog with measured star-formation rates (SFRs) and ultraviolet (UV) photometry from the GALEX Medium Imaging Survey, we derived empirical linear correlations between the SFR to UV luminosity ratio and the UV-optical colors of blue sequence galaxies. The relations provide a simple prescription to correct UV data for dust attenuation that best reconciles the SFRs derived from UV and emission line data. The method breaks down for the red sequence population as well as for very blue galaxies such as the local ``supercompact'' UV luminous galaxies and the majority of high redshift Lyman Break Galaxies which form a low attenuation sequence of their own.