The EDGE-CALIFA survey: Exploring the star formation law through variable selection

Abstract

We present a multilinear analysis to determine the significant predictors of star formation in galaxies using the combined EDGE-CALIFA sample of galaxies. We analyse 1845 kpc-scale lines of sight across 39 galaxies with molecular line emission measurements from EDGE combined with optical IFU data drawn from CALIFA. We use the Least Absolute Shrinkage and Selection Operator (LASSO) to identify significant factors in predicting star formation rates. We find that the local star formation rate surface density is increased by higher molecular gas surface densities and stellar surface densities. In contrast, we see lower star formation rates in systems with older stellar populations, higher gas- and stellar-phase metallicities and larger galaxy masses. We also find a significant increase in star formation rate with galactocentric radius normalized by the disc scale length, which suggests additional parameters regulating star formation rate not explored in this study.