Testing phenomenological and theoretical models of dark matter density profiles with galaxy clusters

TL;DR

This study compares various phenomenological and theoretical dark matter density profiles against gravitational lensing data from galaxy clusters, finding that the BMO and DARKexp models best fit the observed mass distribution.

Contribution

It evaluates the performance of multiple dark matter density models using real galaxy cluster lensing data, highlighting the effectiveness of the BMO and DARKexp profiles.

Findings

BMO profile provides the best fit with the lowest chi-squared.

DARKexp model closely matches the BMO profile's performance.

NFW fits well only when ignoring the 2-halo term.

Abstract

We use the stacked gravitational lensing mass profile of four high-mass (M >~10^{15}Msun) galaxy clusters around z ~ 0.3 from Umetsu et al. to fit density profiles of phenomenological [Navarro-Frenk-White (NFW), Einasto, S\'ersic, Stadel, Baltz-Marshall-Oguri (BMO) and Hernquist] and theoretical (non-singular Isothermal Sphere, DARKexp and Kang & He) models of the dark matter distribution. We account for large-scale structure effects, including a 2-halo term in the analysis. We find that the BMO model provides the best fit to the data as measured by the reduced chi^2. It is followed by the Stadel profile, the generalized NFW profile with a free inner slope and by the Einasto profile. The NFW model provides the best fit if we neglect the 2-halo term, in agreement with results from Umetsu et al. Among the theoretical profiles, the DARKexp model with a single form parameter has the best performance, very close to that of the BMO profile. This may indicate a connection between this theoretical model and the phenomenology of dark matter halos, shedding light on the dynamical basis of empirical profiles which emerge from numerical simulations.