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

Houdt, Josha van and Wel, Arjen van der and Bezanson, Rachel and Franx, Marijn and D'Eugenio, Francesco and Barisic, Ivana and Bell, Eric F. and Gallazzi, Anna and Graaff, Anna de and Maseda, Michael V. and Pacifici, Camilla and Sande, Jesse van de and Sobral, David and Straatman, Caroline and Wu, Po-Feng (2021) Stellar Dynamical Models for 797 z ∼ 0.8 Galaxies from LEGA-C. The Astrophysical Journal, 923 (1): 11. ISSN 0004-637X

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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 lookback 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$\times$ and 2$\times$\re), as well as rotational velocities, velocity dispersions and anisotropy. We show that almost all star-forming galaxies and $\sim$50\% of quiescent galaxies are rotation-dominated, with deprojected $V/\sigma\sim1-2$. 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 lookback time. Together with the additional information on stellar population properties from the LEGA-C spectra, the dynamical mass and $V/\sigma$ measurements presented here create new avenues for studying galaxy evolution at large lookback time.