Galaxy And Mass Assembly (GAMA): The Dependence of Star Formation on Surface Brightness in Low Redshift Galaxies

TL;DR

This study investigates whether galaxy surface brightness influences star formation rates beyond the known correlation with stellar mass, using low-redshift galaxy data from the GAMA survey.

Contribution

It provides evidence that, after accounting for stellar mass, galaxy surface brightness does not significantly affect star formation rates.

Findings

Star formation rate correlates with stellar mass.

No additional dependence on surface brightness was found.

Results are consistent across different galaxy decomposition methods.

Abstract

The star formation rate in galaxies is well known to correlate with stellar mass (the `star-forming main sequence'). Here we extend this further to explore any additional dependence on galaxy surface brightness, a proxy for stellar mass surface density. We use a large sample of low redshift ($z \leq 0.08$) galaxies from the GAMA survey which have both SED derived star formation rates and photometric bulge-disc decompositions, the latter providing measures of disc surface brightness and disc masses. Using two samples, one of galaxies fitted by a single component with S\'{e}rsic index below 2 and one of the discs from two-component fits, we find that once the overall mass dependence of star formation rate is accounted for, there is no evidence in either sample for a further dependence on stellar surface density.