The Morphologies of Massive Galaxies at 1 < z < 3 in the CANDELS-UDS Field

TL;DR

This study uses high-resolution infrared imaging to analyze the morphologies of massive galaxies at 1<z<3, revealing a transition from bulge-dominated to disk-dominated structures over cosmic time.

Contribution

It provides detailed bulge-disk decompositions of ~200 massive galaxies at 1<z<3, highlighting morphological evolution and the disconnect between quenching and structural transformation.

Findings

Massive galaxies at 1<z<2 are mainly mixed bulge+disk systems.

By z>2, these galaxies are predominantly disk-dominated.

A significant fraction of quiescent galaxies are disk-dominated.

Abstract

We have used high-resolution, HST WFC3/IR, near-infrared imaging to conduct a detailed bulge-disk decomposition of the morphologies of ~200 of the most massive (M_star > 10^11 M_solar) galaxies at 1<z<3 in the CANDELS-UDS field. We find that, while such massive galaxies at low redshift are generally bulge-dominated, at redshifts 1<z<2 they are predominantly mixed bulge+disk systems, and by z>2 they are mostly disk-dominated. Interestingly, we find that while most of the quiescent galaxies are bulge-dominated, a significant fraction (25-40%) of the most quiescent galaxies, have disk-dominated morphologies. Thus, our results suggest that the physical mechanisms which quench star-formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies.