2020/01/03 by Adam R. Johnson, Andrew Johnson, L. Rudnick +7 · 1 voice
Physics and Astronomy · #Astrophysics #Cluster (spacecraft) #Coherence (philosophical gambling strategy) #Computational physics #Faraday effect #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Ionosphere and magnetosphere dynamics #Line-of-sight #Magnetic field #Physics #Polarization (electrochemistry) #Quantum mechanics #Scaling #Solar and Space Plasma Dynamics #Statistical physics #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/ab5d30
ApJ, in press
arxiv created 2020/01/03 · arxiv published 2020/01/03 · openalex publication_date 2020/01/10 · arxiv updated 2020/01/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract Magnetic fields play vital roles in intracluster media (ICMs), but estimating their strengths and distributions from observations is a major challenge. Faraday rotation measures (RMs) are widely applied to this task, so it is critical to understand inherent uncertainties in RM analysis. In this paper, we seek to characterize those uncertainties given the types of information available today, independent of the specific technique used. We conduct synthetic RM observations through the ICM of a galaxy cluster drawn from a magnetohydrodynamic cosmological simulation in which the magnetic field is known. We analyze the synthetic RM observations using an analytical formalism based on commonly used model assumptions, allowing us to relate model physical variables to outcome uncertainties. Despite the simplicity of some assumptions, and unknown physical parameters, we are able to extract an approximate magnitude of the central magnetic field within an apparently irreducible uncertain factor of ≈3. Principal, largely irreducible, uncertainties come from the unknown depth along the line of sight of embedded polarized sources, the lack of robust coherence lengths from area-constrained polarization sampling, and the unknown scaling between ICM electron density and magnetic field strength. The RM-estimated central magnetic field strengths span more than an order of magnitude including the full range of synthetic experiments.