The Effect of Environment on Star Formation Activity and Morphology at 0.5 < z < 2.5 in CANDELS

Abstract

To explore the effect of environment on star formation and the 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_* > 10^10.8M_⊙), the effect of environmental quenching is still significant up to z ~ 2.5. No significant environmental dependence is found in the distributions of Sérsic 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 Sérsic index along with stellar mass indicates that morphological transformation is accompanied by star formation quenching.