Central star formation and metallicity in CALIFA interacting galaxies

TL;DR

This study analyzes how galaxy interactions influence star formation and metallicity using integral-field spectroscopic data, revealing moderate central star formation enhancement and complex metallicity changes due to multiple processes.

Contribution

It provides new insights into the effects of galaxy interactions on star formation and metallicity, highlighting the roles of internal processes beyond tidal inflows.

Findings

Interacting galaxies show 2-3 times higher central star formation.

Extended regions have similar star formation in interacting and non-interacting galaxies.

Interacting galaxies have lower metallicities at larger radii compared to controls.

Abstract

We use optical integral-field spectroscopic (IFS) data from 103 nearby galaxies at different stages of the merging event, from close pairs to merger remnants provided by the CALIFA survey, to study the impact of the interaction in the specific star formation and oxygen abundance on different galactic scales. To disentangle the effect of the interaction and merger from internal processes, we compared our results with a control sample of 80 non-interacting galaxies. We confirm the moderate enhancement (2-3 times) of specific star formation for interacting galaxies in central regions as reported by previous studies; however, the specific star formation is comparable when observed in extended regions. We find that control and interacting star-forming galaxies have similar oxygen abundances in their central regions, when normalized to their stellar masses. Oxygen abundances of these interacting galaxies seem to decrease compared to the control objects at the large aperture sizes measured in effective radius. Although the enhancement in central star formation and lower metallicities for interacting galaxies have been attributed to tidally induced inflows, our results suggest that other processes such as stellar feedback can contribute to the metal enrichment in interacting galaxies.