The Calibration of Star Formation Rate Indicators for WISE 22 Micron Selected Galaxies in the SDSS

TL;DR

This study calibrates WISE 22 micron mid-infrared indicators for star formation rates in SDSS galaxies, introducing a non-linear combination of Hα and MIR luminosities to improve accuracy across different metallicities.

Contribution

It presents the first application of a non-linear combination of Hα and MIR luminosities for SFR estimation using WISE data, reducing dependence on metallicity and physical parameters.

Findings

Both 12 and 22 μm luminosities correlate with SFR but underestimate in metal-poor galaxies.

A linear combination of Hα and MIR luminosities mitigates metallicity dependence.

A non-linear combination yields the most accurate SFR estimates with minimal scatter.

Abstract

We study star formation rate (SFR) indicators for Wide-field Infrared Survey Explorer (WISE) 22 \mu m selected, star-forming galaxies at 0.01 < z < 0.3 in the Sloan Digital Sky Survey. Using extinction-corrected H\alpha\ luminosities and total infrared luminosities as reference SFR estimates, we calibrate WISE mid-infrared (MIR) related SFR indicators. Both 12 and 22 \mu m monochromatic luminosities correlate well with the reference SFR estimates, but tend to underestimate SFRs of metal-poor galaxies (at lower than solar metallicity), consistent with previous studies. We mitigate this metallicity dependence using a linear combination of observed H\alpha\ and WISE MIR luminosities for SFR estimates. The combination provides robust SFR measurements as Kennicutt et al. (2009) applied to Spitzer data. However, we find that the coefficient a in L_H\alpha(obs) + a L_MIR increases with SFR, and show that a non-linear combination of observed H\alpha\ and MIR luminosities gives the best SFR estimates with small scatters and with little dependence on physical parameters. Such a combination of H\alpha\ and MIR luminosities for SFR estimates is first applied to WISE data. We provide several SFR recipes using WISE data applicable to galaxies with 0.1 <~ SFR (M_sun yr^-1) <~ 100.