Minor mergers or progenitor bias? The stellar ages of small and large quenched galaxies

Journal Article · Thu Nov 10 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/831/2/173· OSTI ID:22868486

Fagioli, Martina; Carollo, C. Marcella; Lilly, Simon J.; Onodera, Masato; Tacchella, Sandro ^[1]; Renzini, Alvio ^[2]

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1. Institute for Astronomy, ETH Zurich, 8093 Zurich (Switzerland)
2. INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122, Padova (Italy)

We investigate the origin of the evolution of the population-averaged size of quenched galaxies (QGs) through a spectroscopic analysis of their stellar ages. This evolution has been claimed to arise from either the size growth of individual galaxies through a sequence of dry minor mergers, or the addition of larger, newly quenched galaxies to the pre-existing population (i.e., a progenitor bias effect). We use the 20k zCOSMOS-bright spectroscopic survey to select bona fide QGs at 0.2 < z < 0.8. We stack their spectra in bins of redshift, stellar mass, and size to compute stellar population parameters through fits to the rest-frame optical spectra and Lick indices. The size–age relation differs below and above ∼10{sup 11} M {sub ⊙}: at 10.5

• OSTI ID: 22868486
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 831; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
GALACTIC EVOLUTION
GALAXIES
MASS
RED SHIFT
SPECTRA
UNIVERSE