# The KMOS Cluster Survey (KCS) I:The fundamental plane and the formation ages of cluster galaxies at redshift $1.4z1.6$

Beifiori, Alessandra and Mendel, J. Trevor and Chan, Jeffrey C. C. and Saglia, Roberto P. and Bender, Ralf and Cappellari, Michele and Davies, Roger L. and Galametz, Audrey and Houghton, Ryan C. W. and Prichard, Laura J. and Smith, Russel and Stott, John P. and Wilman, David J. and Lewis, Ian J. and Sharples, Ray and Wegner, Michael (2017) The KMOS Cluster Survey (KCS) I:The fundamental plane and the formation ages of cluster galaxies at redshift $1.4z1.6$. The Astrophysical Journal, 846 (2). ISSN 0004-637X

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## Abstract

We present the analysis of the fundamental plane (FP) for a sample of 19 massive red-sequence galaxies ($M_{\star} >4\times10^{10} M_{\odot}$) in 3 known overdensities at $1.39z 11$) in our sample, we translate the FP zero-point evolution into a mass-to-light-ratio $M/L$ evolution finding $\Delta \log M/L_{B}=(-0.46\pm0.10)z$, $\Delta \log M/L_{B}=(-0.52\pm0.07)z$, to $\Delta \log M/L_{B}=(-0.55\pm0.10)z$, respectively. We assess the potential contribution of the galaxies structural and stellar velocity dispersion evolution to the evolution of the FP zero-point and find it to be $\sim$6-35 % of the FP zero-point evolution. The rate of $M/L$ evolution is consistent with galaxies evolving passively. By using single stellar population models, we find an average age of $2.33^{+0.86}_{-0.51}$ Gyr for the $\log M_{\star}/M_{\odot}>11$ galaxies in our massive and virialized cluster at $z=1.39$, $1.59^{+1.40}_{-0.62}$ Gyr in a massive but not virialized cluster at $z=1.46$, and $1.20^{+1.03}_{-0.47}$ Gyr in a protocluster at $z=1.61$. After accounting for the difference in the age of the Universe between redshifts, the ages of the galaxies in the three overdensities are consistent within the errors, with possibly a weak suggestion that galaxies in the most evolved structure are older.

Item Type:
Journal Article
Journal or Publication Title:
The Astrophysical Journal
This is an author-created, un-copyedited version of an article accepted for publication/published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.3847/1538-4357/aa8368
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
Departments:
ID Code:
87355
Deposited By:
Deposited On:
14 Aug 2017 15:20
Refereed?:
Yes
Published?:
Published