Title: Stellar populations in z=0.8-1.0 cluster galaxies: 
  Constraints on galaxy evolution

Authors: Inger Jorgensen, Kristin Chiboucas, Kathleen Flint, 
  Alexander Fritz, Jordi Barr, Ricardo Schiavon

Abstract:
High S/N optical spectroscopy obtained with Gemini/GMOS and HST/ACS imaging 
for three rich galaxy clusters at z=0.8-1.0 are used to establish the 
Fundamental Plane and scaling relations for spectroscopic line indices of 
E and S0 galaxies in these clusters. The data represent the deepest study 
of its kind at these redshifts. The data provide constraints on the mass 
dependent evolution of the galaxies and effects of abundance variations. 
The lowest mass galaxies in the sample (Mass=10^10.3 Msun) have experienced 
their last major episode of star formation only ~1 Gyr prior to the epoch 
at which we observe them. The high mass galaxies in the sample 
(Mass>10^11.3 Msun) had their last star formation episode at z>1.6.
The galaxies in the three clusters show significant differences in the
strength of the CN and Fe indices, which may be caused by differences in
abundance ratios. Differences in the abundance ratios are in disagreement
passive evolution for E and S0 galaxies between z=1 and the present.