Probing possible effects of circumgalactic media on the metal content of galaxies through the mass-metallicity relationship

TL;DR

This study investigates whether the circumgalactic medium influences the metal content in galaxies by analyzing galaxy pairs and finds no significant effect on metallicity distribution.

Contribution

It provides observational evidence that sharing the circumgalactic medium does not significantly impact the metallicity differences in galaxy pairs.

Findings

No significant metallicity difference in galaxy pairs versus control.

Metallicity differences are unaffected by star formation rate and stellar mass ratio.

Sharing the CGM may not influence galaxy metal evolution.

Abstract

The circumgalactic medium (CGM) connects the gas between the interstellar medium (ISM) and the intergalactic medium, which plays an important role in galaxy evolution. We use the stellar mass-metallicity relationship to investigate whether sharing the CGM will affect the distribution of metals in galaxy pairs. The optical emission lines from the Sloan Digital Sky Survey Data Release (SDSS DR7) are used to measure the gas-phase metallicity. We find that there is no significant difference in the distribution of the metallicity difference between two members in star forming-star forming pairs ($\rm \Delta log(O/H)_{diff}$), metallicity offset from the best-fitted stellar mass-metallicity relationship of galaxies in pairs ($\rm \Delta log(O/H)_{MS}$), as compared to "fake" pairs. By looking at $\rm \Delta log(O/H)_{diff}$ and $\rm \Delta log(O/H)_{MS}$ as a function of the star formation rate (SFR), specific star formation rate (sSFR), and stellar mass ratio, no difference is seen between galaxies in pairs and control galaxies. From our results, the share of the CGM may not play an important role in shaping the evolution of metal contents of galaxies.