The recent star formation histories of nearby galaxies on resolved scales

Abstract

Abstract Star formation histories (SFHs) of galaxies are affected by a variety of factors, both external (field vs. cluster/group) and internal (presence of a bar and AGN, morphological type). In this work, we extend our previous study and apply the $\langle SFR_{\rm {5}} \rangle \big / \langle SFR_{\rm {200}} \rangle$ metric to a sample of eleven nearby galaxies with MUSE observations. Based on a combination of Hα and UV photometry, $\langle SFR_{\rm {5}} \rangle \big / \langle SFR_{\rm {200}} \rangle$ is sensitive to star formation timescales of ∼5–200 Myr and therefore measures the present-day rate of change in the star formation rate, dSFR/dt. Within this limited galaxy sample, we do not observe systematic variations between the global value of $\langle SFR_{\rm {5}} \rangle \big / \langle SFR_{\rm {200}} \rangle$ and the presence of an active galactic nucleus, stellar bar, nor with group or cluster membership. Within some of the individual galaxies, we however observe significant differences in $\langle SFR_{\rm {5}} \rangle \big / \langle SFR_{\rm {200}} \rangle$ between the arm and interarm regions. In half of the galaxies, the recent SFH of both arm and interarm regions has been very similar. However, in the galaxies with higher bulge-to-total light ratios and earlier morphological type, the SFR is declining more rapidly in the interarm regions. This decline in SFR is not a result of low molecular gas surface density or a decrease in the star formation efficiency, implying that other factors are responsible for this SFR decrease.