Stellar Dynamical Models for 797 z 0.8 Galaxies from LEGA-C

Abstract

We present spatially resolved stellar kinematics for 797 z = 0.6-1 galaxies selected from the LEGA-C survey and construct axisymmetric Jeans models to quantify their dynamical mass and degree of rotational support. The survey is K _s -band selected, irrespective of color or morphological type, and allows for a first assessment of the stellar dynamical structure of the general L* galaxy population at large look-back time. Using light profiles from Hubble Space Telescope imaging as a tracer, our approach corrects for observational effects (seeing convolution and slit geometry), and uses well-informed priors on inclination, anisotropy, and a non-luminous mass component. Tabulated data include total mass estimates in a series of spherical apertures (1, 5, and 10 kpc; 1 × and 2 × R _e), as well as rotational velocities, velocity dispersions, and anisotropy. We show that almost all star-forming galaxies and ~50% of quiescent galaxies are rotation dominated, with deprojected V/σ ~ 1-2. Revealing the complexity in galaxy evolution, we find that the most massive star-forming galaxies are among the most rotation dominated, and the most massive quiescent galaxies among the least rotation-dominated galaxies. These measurements set a new benchmark for studying galaxy evolution, using stellar dynamical structure for galaxies at large look-back time. Together with the additional information on stellar population properties from the LEGA-C spectra, the dynamical mass and V/σ measurements presented here create new avenues for studying galaxy evolution at large look-back time.