Astrophys. J., 808, 161 (2015/August-1)
The ages, metallicities, and element abundance ratios of massive quenched galaxies at z = 1.6.
ONODERA M., CAROLLO C.M., RENZINI A., CAPPELLARI M., MANCINI C., ARIMOTO N., DADDI E., GOBAT R., STRAZZULLO V., TACCHELLA S. and YAMADA Y.
Abstract (from CDS):
We investigate the stellar population properties of a sample of 24 massive quenched galaxies at 1.25 < zspec < 2.09 identified in the COSMOS field with our Subaru/Multi-object Infrared Camera and Spectrograph near-IR spectroscopic observations. Tracing the stellar population properties as close to their major formation epoch as possible, we try to put constraints on the star formation history, post-quenching evolution, and possible progenitor star-forming populations for such massive quenched galaxies. By using a set of Lick absorption line indices on a rest-frame optical composite spectrum, the average age, metallicity [Z/H], and α-to-iron element abundance ratio [α/Fe] are derived as,, and, respectively. If our sample of quenched galaxies at is evolved passively to z = 0, their stellar population properties will align in excellent agreement with local counterparts at similar stellar velocity dispersions, which qualifies them as progenitors of local massive early-type galaxies. Redshift evolution of stellar population ages in quenched galaxies combined with low redshift measurements from the literature suggests a formation redshift of, around which the bulk of stars in these galaxies have been formed. The measured [α/Fe] value indicates a star formation timescale of Gyr, which can be translated into a specific star formation rate of prior to quenching. Based on these findings, we discuss identifying possible progenitor star-forming galaxies at. We identify normal star-forming galaxies, i.e., those on the star-forming main sequence, followed by a rapid quenching event, as likely precursors of the quenched galaxies at presented here.
galaxies: abundances - galaxies: evolution - galaxies: formation - galaxies: high-redshift - galaxies: stellar content
Table 1: [ORC2012] NNNNNN N=10 among (Nos 401700-543256) added.
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