Correlations between MIR, FIR, H$\alpha$, and FUV Luminosities for SWIRE galaxies

TL;DR

This study investigates the correlations between various infrared, H-alpha, and FUV luminosities in different galaxy types, confirming tight relationships and refining star formation rate estimations using multi-wavelength data from the SWIRE survey.

Contribution

It provides a comprehensive analysis of luminosity correlations across galaxy types, re-calibrates SFR formulas, and confirms the tightness of certain MIR-FIR relationships, enhancing understanding of galaxy emission properties.

Findings

MIR luminosities correlate well with H-alpha, TIR, and FUV luminosities.

Re-calibration of MIR-derived SFR formulas with less than 15% difference.

Tightest correlations found between 24μm and 70μm, and 8μm[dust] and 160μm luminosities.

Abstract

e present and analyze the correlations between mid-infrared (MIR), far-infrared (FIR), total-infrared (TIR), H$\alpha$, and FUV luminosities for star-forming galaxies, composite galaxies and AGNs, based on a large sample of galaxies selected from the $Spitzer$ SWIRE fields. The MIR luminosities of star-forming galaxies are well correlated with their H$\alpha$, TIR and FUV luminosities, and we re-scaled the MIR-derived SFR formulae according to the above correlations with differences less than 15%. We confirm the recent result by calzetti et al. (2007) that the combined observed H$\alpha$ + 24$\mu$m luminosities L(H$\alpha$$_{\rm obs}$+ 24$\mu$m) possess very tight correlation with the extinction-corrected H$\alpha$ luminosities L(H$\alpha$$\_$corr) for star-forming and even for dwarf galaxies, and show that the combined L(H$\alpha$$_{\rm obs}$+ 8$\mu$m[dust]) are also tightly correlated with L(H$\alpha$$\_$corr) for the above sample galaxies. Among all the L(MIR)-L(FIR) correlations for star-forming galaxies, the L(24$\mu$m) vs. L(70$\mu$m) and L(8$\mu$m[dust]) vs. L(160$\mu$m) are the tightest and also nearly linear. The former could be related to young massive star formation, while the latter might be relevant to diffuse dust emissions heated by old stellar populations. Composite galaxies and AGNs have higher MIR-to-H$\alpha$/MIR-to-FUV luminosity ratios than star-forming galaxies, nevertheless their correlations among MIR, FIR and TIR luminosities are completely following those of star-forming galaxies.