Joint Analysis of Cluster Observations. I. Mass Profile of Abell 478 from Combined X‐Ray, Sunyaev‐Zel’dovich, and Weak‐Lensing Data

We provide a new framework for the joint analysis of cluster observations(JACO) using simultaneous fits to X-ray, Sunyaev-Zel'dovich (SZ), and weaklensing data. Our method fits the mass models simultaneously to all data,provides explicit separation of the gaseous, dark, and stellar components,and--for the first time--allows joint constraints on all measurable physicalparameters. JACO includes additional improvements to previous X-ray techniques,such as the treatment of the cluster termination shock and explicit inclusionof the BCG's stellar mass profile. An application of JACO to the rich galaxycluster Abell 478 shows excellent agreement among the X-ray, lensing, and SZdata. We find that Abell 478 is consistent with a cuspy dark matter profilewith inner slope n=1. Accounting for the stellar mass profile of the BCG allowsus to rule out inner dark matter slopes n>1.1 at the 99% confidence level. Atlarge radii, an 1/r^3 asymptotic slope is preferred over an 1/r^4 behavior. Allsingle power law dark matter models are ruled out at greater than the 99%confidence level. JACO shows that self-consistent modeling of multiwavelengthdata can provide powerful constraints on the shape of the dark profile.Comment: 19 pages, 8 figures; accepted for publication in The Astrophysical Journa