Environmental dependence of galaxy properties in the southern GAMA regions

TL;DR

This study analyzes how galaxy properties like color, mass, and star formation rate depend on local environment using GAMA survey data, revealing strong correlations especially for galaxy color and sSFR, and assessing the impact of observational biases.

Contribution

It provides new insights into environmental effects on galaxy properties in the southern GAMA regions, expanding previous analyses to these less-studied areas and evaluating observational biases.

Findings

Galaxy color correlates strongly with local overdensity.

Star formation rate decreases with increasing density.

Environmental effects are consistent across different GAMA regions.

Abstract

Using data from the Galaxy and Mass Assembly (GAMA) survey, we investigate how galaxy properties correlate with the local environment, focusing on the two southern regions of the survey (G02 and G23) that have not previously been examined in this context. We employ two-point and marked correlation functions to quantify the environmental dependence of galaxy color, stellar mass, luminosity across the $u$, $g$, $r$, $J$, and $K$ bands, as well as star formation rate (SFR) and specific star formation rate (sSFR). We also assess the impact of redshift incompleteness and cosmic variance on these clustering measurements. Our results show that $u-r$ and $g-r$ colors are most strongly correlated with local overdensity, followed by stellar mass. The sSFR exhibits a clear inverse relationship with density of the environment, consistent with the trend observed for $u$-band luminosity, which traces young stellar populations. In contrast, galaxies brighter in the $g$, $J$, and $K$ bands preferentially inhabit denser regions. By comparing our measurements from the southern regions with those from the equatorial regions of GAMA, we find that cosmic variance does not significantly influence our conclusions. However, redshift incompleteness affects the clustering measurements, as revealed through comparisons of subsets within the G02 region. The measured correlations provide key constraints for models of galaxy assembly across mass and environment, while the environmental trends in color and near-infrared luminosity offer a means to trace stellar mass growth and quenching with redshift.