2008/04/30 by Arjen van der Wel, Roeland P. van der Marel · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Elliptical galaxy #Fundamental plane (elliptical galaxies) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Lenticular galaxy #Luminosity #Redshift #Stellar, planetary, and galactic studies #Surface brightness #Surface brightness fluctuation #Velocity dispersion #astro-ph
paper · pdf · doi:10.1086/589734
To appear in ApJ 683 (9 pages, 7 figures). Minor changes included to match published version
arxiv created 2008/06/20 · openalex publication_date 2008/08/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We use the spatial information of our previously published VLT/FORS2 absorption-line spectroscopy to measure mean stellar velocity and velocity dispersion profiles of 25 field early-type galaxies at a median redshift z = 0.97 (full range 0.6 < z < 1.2). This provides the first detailed study of early-type galaxy rotation at these redshifts. From surface brightness profiles from HST imaging we calculate two-integral oblate axisymmetric Jeans equation models for the observed kinematics. Fits to the data yield for each galaxy the degree of rotational support and the mass-to-light ratio M / L Jeans . S0 and Sa galaxies are generally rotationally supported, whereas elliptical galaxies rotate less rapidly or not at all. Down to M B = − 19.5 (corrected for luminosity evolution), we find no evidence for evolution in the fraction of rotating early-type (E+S0) galaxies between z ∼ 1 (63% ± 11% ) and the present (61% ± 5% ). We interpret this as evidence for little or no change in the field S0 fraction with redshift. We compare M / L Jeans with M / L vir inferred from the virial theorem and globally averaged quantities and assuming homologous evolution. There is good agreement for nonrotating (mostly E) galaxies. However, for rotationally supported galaxies (mostly S0) M / L Jeans is on average ~40% higher than M / L vir . We discuss possible explanations and the implications for the evolution of M / L between z = 1 and the present and its dependence on mass.