Reconstructing the projected gravitational potential of galaxy clusters from galaxy kinematics
Abstract
We develop a method for reconstructing the two-dimensional, projected gravitational potential of galaxy clusters from observed line-of-sight velocity dispersions of cluster galaxies. It is the third of an intended series of papers aiming at a unique reconstruction method for cluster potentials combining lensing, X-ray, Sunyaev-Zel'dovich and kinematic data. The observed galaxy velocity dispersions are deprojected using the Richardson-Lucy algorithm. The obtained radial velocity dispersions are then related to the gravitational potential by using the tested assumption of a polytropic relation between the effective galaxy pressure and the density. Once the gravitational potential is obtained in three dimensions, projection along the line-of-sight yields the two-dimensional potential. For simplicity we adopt spherical symmetry and a known profile for the anisotropy parameter of the galaxy velocity dispersions. We test the method with a numerically simulated galaxy cluster and galaxies identified therein. We extract a projected velocity-dispersion profile from the simulated cluster and pass it through our algorithm, showing that the deviation between the true and the reconstructed gravitational potential is less then 10% within approximately 1.2 Mpc/h from the cluster centre.
Keywords
Cite
@article{arxiv.1304.7681,
title = {Reconstructing the projected gravitational potential of galaxy clusters from galaxy kinematics},
author = {Eleonora Sarli and Sven Meyer and Massimo Meneghetti and Sara Konrad and Charles L. Majer and Matthias Bartelmann},
journal= {arXiv preprint arXiv:1304.7681},
year = {2015}
}
Comments
8 pages, submitted to A&A