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The Evolution of a Mass-Selected Sample of Early-Type Field Galaxies

D. Rusin·C. S. Kochanek·E. E. Falco·C. R. Keeton·B. A. McLeod·C. D. Impey·J. Lehar·J. A. Munoz·C. Y. Peng·H. -W. Rix
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Abstract

We investigate the evolution of mass-selected early-type field galaxies using a sample of 28 gravitational lenses spanning the redshift range 0 < z < 1. Based on the redshift-dependent intercept of the fundamental plane in the rest frame B band, we measure an evolution rate of d log (M/L)_B / dz = -0.56 +/- 0.04 (all errors are 1 sigma unless noted) if we directly compare to the local intercept measured from the Coma cluster. Re-fitting the local intercept helps minimize potential systematic errors, and yields an evolution rate of d log (M/L)_B / dz = -0.54 +/- 0.09. An evolution analysis of properly-corrected aperture mass-to-light ratios (defined by the lensed image separations) is closely related to the Faber-Jackson relation. In rest frame B band we find an evolution rate of d log (M/L)_B / dz = -0.41 +/- 0.21, a present-day characteristic magnitude of M_{*0} = -19.70 + 5 log h +/- 0.29 (assuming a characteristic velocity dispersion of sigma_{DM*} = 225 km/s), and a Faber-Jackson slope of gamma_{FJ} = 3.29 +/- 0.58. The measured evolution rates favor old stellar populations (mean formation redshift z_f > 1.8 at 2 sigma confidence for a Salpeter initial mass function and a flat Omega_m =0.3 cosmology) among early-type field galaxies, and argue against significant episodes of star formation at z < 1.

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D. Rusin, C. S. Kochanek, E. E. Falco, C. R. Keeton, B. A. McLeod, C. D. Impey, J. Lehar, J. A. Munoz, C. Y. Peng, H. -W. Rix. 2002-12-20. The Evolution of a Mass-Selected Sample of Early-Type Field Galaxies. https://doi.org/10.1086/346206

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