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The KMOS Cluster Survey (KCS). III. Fundamental Plane of Cluster Galaxies at z ≃ 1.80 in JKCS 041

Prichard, Laura J.; Davies, Roger L.; Beifiori, Alessandra; Chan, Jeffrey C.C.; Cappellari, Michele; Houghton, Ryan C.W.; Mendel, J. Trevor; Bender, Ralf; Galametz, Audrey; Saglia, Roberto P.; Stott, John P.; Wilman, David J.; Lewis, Ian J.; Sharples, Ray; Wegner, Michael

The KMOS Cluster Survey (KCS). III. Fundamental Plane of Cluster Galaxies at z ≃ 1.80 in JKCS 041 Thumbnail


Laura J. Prichard

Roger L. Davies

Alessandra Beifiori

Jeffrey C.C. Chan

Michele Cappellari

Ryan C.W. Houghton

J. Trevor Mendel

Ralf Bender

Audrey Galametz

Roberto P. Saglia

John P. Stott

David J. Wilman

Ian J. Lewis

Michael Wegner


We present data for 16 galaxies in the overdensity JKCS 041 at $z\simeq 1.80$ as part of the K-band Multi-Object Spectrograph (KMOS) Cluster Survey (KCS). With 20 hr integrations, we have obtained deep absorption-line spectra from which we derived velocity dispersions for seven quiescent galaxies. We combined photometric parameters derived from Hubble Space Telescope images with the dispersions to construct a fundamental plane (FP) for quiescent galaxies in JKCS 041. From the zero-point evolution of the FP, we derived a formation redshift for the galaxies of ${z}_{\mathrm{form}}=3.0\pm 0.3$, corresponding to a mean age of 1.4 ± 0.2 Gyr. We tested the effect of structural and velocity dispersion evolution on our FP zero-point and found a negligible contribution when using dynamical mass-normalized parameters ($\sim 3 \% $) but a significant contribution from stellar-mass-normalized parameters ($\sim 42 \% $). From the relative velocities of the galaxies, we probed the 3D structure of these 16 confirmed members of JKCS 041 and found that a group of galaxies in the southwest of the overdensity had systematically higher velocities. We derived ages for the galaxies in the different groups from the FP. We found that the east-extending group had typically older galaxies (${2.1}_{-0.2}^{+0.3}$ Gyr) than those in the southwest group (0.3 ± 0.2 Gyr). Although based on small numbers, the overdensity dynamics, morphology, and age results could indicate that JKCS 041 is in formation and may comprise two merging groups of galaxies. This result could link large-scale structure to ages of galaxies for the first time at this redshift.


Prichard, L. J., Davies, R. L., Beifiori, A., Chan, J. C., Cappellari, M., Houghton, R. C., …Wegner, M. (2017). The KMOS Cluster Survey (KCS). III. Fundamental Plane of Cluster Galaxies at z ≃ 1.80 in JKCS 041. Astrophysical Journal, 850(2), Article 203.

Journal Article Type Article
Acceptance Date Oct 25, 2017
Online Publication Date Dec 4, 2017
Publication Date Dec 4, 2017
Deposit Date Jan 5, 2018
Publicly Available Date Jan 5, 2018
Journal Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 850
Issue 2
Article Number 203


Published Journal Article (6 Mb)

Copyright Statement
© 2017. The American Astronomical Society. All rights reserved.

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