Galaxy And Mass Assembly (GAMA): the interplay between galaxy mass, SFR and heavy element abundance in paired galaxy sets

TL;DR

This study investigates how galaxy interactions influence star formation rates and metallicity, revealing that pair multiplicity, separation, and dynamics significantly affect these properties in galaxy pairs.

Contribution

It provides the first analysis of SFR and metallicity variations across different multiplicities, pair types, and dynamical states in a large galaxy pair sample.

Findings

SFR is enhanced by 0.025-0.15 dex in multiple pairs.

Major and minor pairs show up to 2-4 times SFR increase.

Metallicity decreases by up to 0.08 dex in close pairs.

Abstract

We study the star formation rate (SFR), stellar mass ($M_{\star}$) and the gas metallicity (Z) for 4,636 galaxy pairs using the Galaxy And Mass Assembly (GAMA) survey. Our galaxy pairs lie in a redshift range of 0 $<$ $z$ $<$ 0.35, mass range of 7.5 $<$ log( M$_{\star}$/ M$_\odot$) $<$ 11.5 and $\Delta V$ $<$ 1000 km s$^{-1}$. We explore variations in SFR and Z from three point of views: multiplicity, pair separation and dynamics. We define multiplicity as the number of galaxies paired with a single galaxy, and analyzed for the first time variations in SFR and Z for both, single pairs and pairs with higher multiplicity. For the latter, we find SFR enhancements from 0.025-0.15 dex, that would shift the M-SFR relation of single pairs by 27$\%$ to higher SFRs. The effect of Z on the other hand, is of only 4$\%$. We analyze the most and least massive galaxy of major/minor pairs as a function of the pair separation. We define major pairs those with mass ratios of 0.5 $<$ $M_1$/$M_2$ $<$ 2, while pairs with more discrepant mass ratios are classified as minor pairs. We find SFR enhancements of up to 2 and 4 times with respect to their control sample, for major and minor pairs. For the case of Z, we find decrements of up to 0.08 dex for the closest pairs. When we focus on dynamics, Z enhancements are found for minor pairs with high velocity dispersion $(\sigma_p > 250 \; \mathrm{km\,s ^{-1}})$ and high multiplicity.