Calibration of ultraviolet, mid-infrared and radio star formation rate indicators

TL;DR

This paper provides new calibrations for star formation rate indicators across ultraviolet, mid-infrared, and radio bands, including one of the first direct calibrations at 150 MHz, based on a sample of 66 nearby galaxies.

Contribution

It introduces novel calibrations for star formation rates using multiple wavelength indicators, notably including the first direct calibration at 150 MHz.

Findings

WISE W4, Spitzer 24 micron, and 1.4 GHz show tight correlations with H-alpha luminosity.

Calibrations are consistent with prior literature for L* galaxies but differ significantly for dwarf galaxies.

The calibrations have low scatter, indicating high reliability.

Abstract

We present calibrations for star formation rate indicators in the ultraviolet, mid-infrared and radio continuum bands, including one of the first direct calibrations of 150 MHz as a star formation rate indicator. Our calibrations utilize 66 nearby star forming galaxies with Balmer decrement corrected H-alpha luminosities, which span 5 orders of magnitude in star formation rate and have absolute magnitudes of -24<M_r<-12. Most of our photometry and spectrophotometry is measured from the same region of each galaxy, and our spectrophotometry has been validated with SDSS photometry, so our random and systematic errors are small relative to the intrinsic scatter seen in star formation rate indicator calibrations. We find WISE W4 (22.8 micron), Spitzer 24 micron and 1.4 GHz have tight correlations with Balmer decrement corrected H-alpha luminosity, with scatter of only 0.2 dex. Our calibrations are comparable to those from the prior literature for L* galaxies, but for dwarf galaxies our calibrations can give star formation rates that are far greater than those derived from much of the prior literature.