The effect of environment on star formation activity and morphology at 0.5 < z < 2.5 in CANDELS

TL;DR

This study investigates how environment influences star formation and galaxy morphology at redshifts 0.5 to 2.5, finding environment mainly affects quiescent fraction, while morphology correlates more with star formation status.

Contribution

It provides a robust Bayesian-based method to estimate local galaxy overdensity and analyzes its impact on galaxy properties across five CANDELS fields.

Findings

Quiescent fraction increases with overdensity and stellar mass.

Environmental quenching is significant for low-mass galaxies at 0.5<z<1.

Morphological parameters are mainly linked to star formation status.

Abstract

To explore the effect of environment on star-formation and morphological transformation of high-redshift galaxies, we present a robust estimation of localized galaxy overdensity using a density estimator within the Bayesian probability framework.The maps of environmental overdensity at $0.5< z< 2.5$ are constructed for the five CANDELS fields. In general, the quiescent fraction increases with overdensity and stellar mass. Stellar mass dominates the star formation quenching for massive galaxies, while environmental quenching tends to be more effective for the low-mass galaxies at $0.5< z < 1$. For the most massive galaxies ($M_* > 10^{10.8} M_{\odot}$), the effect of environmental quenching is still significant up to $z \sim 2.5$. No significant environmental dependence is found in the distributions of S\'{e}rsic index and effective radius for SFGs and QGs separately. The primary role of environment might be to control the quiescent fraction. And the morphological parameters are primarily connected with star formation status. The similarity in the trends of quiescent fraction and S\'{e}rsic index along with stellar mass indicates that morphological transformation is accompanied with star formation quenching.