Oyarzun, Grecco A. and Bundy, Kevin and Westfall, Kyle B. and Belfiore, Francesco and Thomas, Daniel and Maraston, Claudia and Lian, Jianhui and Aragon-Salamanca, Alfonso and Zheng, Zheng and Gonzalez-Perez, Violeta and Law, David R. and Drory, Niv and Andrews, Brett H. (2019) Signatures of stellar accretion in MaNGA early-type galaxies. The Astrophysical Journal, 880 (2): 111. ISSN 0004-637X
Abstract
The late assembly of massive galaxies is thought to be dominated by stellar accretion in their outskirts (beyond 2 effective radii Re) due to dry, minor galaxy mergers. We use observations of 1010 passive early-type galaxies (ETGs) within z10^{11}Msun ETGs. This is a signature of stellar accretion. Based on a toy model for stellar metallicity profiles, we infer the ex-situ stellar mass fraction in ETGs as a function of M and galactocentric radius. We find that ex-situ stars at 2Re make up 20% of the projected stellar mass of M10^{11.5}Msun ETGs.