The structure of massive quiescent galaxies at z~3 in the CANDELS-COSMOS field

TL;DR

This study identifies massive quiescent galaxies at z~3 in the CANDELS-COSMOS field, revealing their compact sizes, disk-like structures, and potential evolutionary links to local early-type galaxies through inside-out growth.

Contribution

It introduces a two-color selection method to find high-redshift quiescent galaxies and analyzes their sizes, structures, and evolution, providing new insights into galaxy formation at z~3.

Findings

pVJL galaxies are 3-4 times smaller than local ETGs of similar mass

Most pVJL galaxies are disk-dominated with low Sersic index

High-redshift compact galaxies likely form the cores of local ETGs

Abstract

In this letter, we use a two-color (J-L) vs. (V-J) selection criteria to search massive, quiescent galaxy candidates at 2.5<z<4.0 in the CANDELS-COSMOS field. We construct a H-selected catalogue and complement it with public auxiliary data. We finally obtain 19 passive VJL-selected (hereafter pVJL) galaxies as the possible massive quiescent galaxy candidates at z~3 by several constrains. We find the sizes of our pVJL galaxies are on average 3-4 times smaller than those of local ETGs with analogous stellar mass. The compact size of these z~3 galaxies can be modelled by assuming their formation at z ~ 4-6 according to the dissipative collapse of baryons. Up to z<4, the mass-normalized size evolution can be described by $r_e\propto (1+z)^{-1.0}$. Low Sersic index and axis ratio, with median values n~1.5 and b/a~0.65 respectively, indicate most of pVJL galaxies are disk-dominated. Despite large uncertainty, the inner region of the median mass profile of our pVJL galaxies is similar to those of quiescent galaxies (QGs) at 0.5<z<2.5 and local Early-type galaxies (ETGs). It indicates local massive ETGs have been formed according to an inside-out scenario: the compact galaxies at high redshift make up the cores of local massive ETGs and then build up the outskirts according to dissipationless minor mergers.