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arXiv · 1711.10018

Deriving galaxy cluster velocity anisotropy profiles from a joint analysis of dynamical and weak lensing data

Alejo Stark·Christopher J. Miller·Vitali Halenka
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Abstract

We present an analytic approach to lift the mass-anisotropy degeneracy in clusters of galaxies by utilizing the line-of-sight velocity dispersion of clustered galaxies jointly with weak lensing inferred masses. More specifically, we solve the spherical Jeans equation by assuming a simple relation between the line-of-sight velocity dispersion and the radial velocity dispersion and recast the Jeans equation as a Bernoulli differential equation that has a well-known analytic solution. We first test our method in cosmological N-body simulations and then derive the anisotropy profiles for 35 archival data galaxy clusters with an average redshift of $\langle {z}_{c}\rangle =0.25$. The resulting profiles yield a weighted average global value of $\langle β(0.2\leqslant R/{R}_{200}\leqslant 1)\rangle =0.35\pm 0.28$ (stat) \pm 0.15 (sys). This indicates that clustered galaxies tend to globally fall on radially anisotropic orbits. We note that this is the first attempt to derive velocity anisotropy profiles for a cluster sample of this size utilizing joint dynamical and weak lensing data

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Alejo Stark, Christopher J. Miller, Vitali Halenka. 2019-05-26. Deriving galaxy cluster velocity anisotropy profiles from a joint analysis of dynamical and weak lensing data. https://doi.org/10.3847/1538-4357%2Fab06fa

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