The recent star formation histories of nearby galaxies on resolved scales

TL;DR

This study investigates the recent star formation histories of nearby galaxies on resolved scales using a new metric, revealing that internal galaxy features influence star formation decline more than external environment.

Contribution

It applies the <SFR5>/<SFR200> metric to spatially resolved galaxy data, providing new insights into how internal structures affect recent star formation activity.

Findings

No systematic variation of <SFR5>/<SFR200> with AGN, bars, or environment.

Significant arm-interarm differences in <SFR5>/<SFR200> in some galaxies.

Higher bulge-to-total ratio galaxies show faster SFR decline in interarm regions.

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 <SFR5>/<SFR200> metric to a sample of eleven nearby galaxies with MUSE observations. Based on a combination of H$\alpha$ and UV photometry, <SFR5>/<SFR200> 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 <SFR5>/<SFR200> 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 <SFR5>/<SFR200> 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.