An adaptive mesh refinement simulation of galaxy cluster formation was performed that included the passive evolution of a magnetic field. It was found that structure formation plays an important role in amplifying large-scale magnetic fields and that the magnetic properties of the obtained cluster were in good agreement with recent observations.
The initial field was amplified by a factor of up to 1000 during the formation of the cluster, and the field strength was seen to be well correlated with the gas density. We further found a magnetic energy power spectrum that is well described by -5/3 Kolmogorov-type turbulence. Near the accretion shocks on the outskirts of the cluster, the magnetic field is amplified well beyond the value expected from mere compression of gas. Here, shear flows lead to a substantial increase in field strength.
Realistic Faraday rotation measures were obtained from the
simulation data, which was however not resolved well-enough to allow for a more quantitative analysis.
Inhaltsverzeichnis (Table of Contents)
- Introduction
- Galaxy Clusters: Formation and General Properties
- Theories Regarding the Origin of Cluster Magnetic Fields.
- Measuring Cluster Magnetic Fields: Methods and Results.
- Synchrotron radiation
- Inverse Compton effect
- Faraday rotation maps
- Reconciling magnetic fields derived from the three methods
- The RM debate.
- Improved methods to determine the magnetic fields from rotation maps
- Simulations of Galaxy Clusters Involving Magnetic Fields . . .
- Theoretical Considerations
- Friedman equation
- Comoving coordinate transformation
- Poisson equation
- General considerations of magnetohydrodynamics
- MHD continuity equation
- MHD momentum conservation
- Energy conservation
- MHD magnetic field evolution
- Methods
- Principle and Initial Conditions
- Cosmology. .
- Gravitational interaction of gas and dark matter
- Adaptive Mesh Refinement
- Hydrodynamics and the Riemann problem
- Evolution of the magnetic field.
- Results
- Structure formation .
- Evolution of the magnetic field.
- Properties of the final cluster
- Correlation of the density and the magnetic field strength
- Power spectrum of the magnetic energy.
- Rotation maps
- Summary and Outlook
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This paper investigates the formation and evolution of magnetic fields in galaxy clusters through numerical simulations. The primary objective is to determine how these fields are amplified during cluster formation and their impact on the cluster's properties. The paper aims to analyze the magnetic field structure and its correlation with the gas density and other characteristics of the cluster.
- Formation and Evolution of Magnetic Fields in Galaxy Clusters
- Amplification of Magnetic Fields During Cluster Formation
- Impact of Magnetic Fields on Cluster Properties
- Correlation of Magnetic Field Strength with Gas Density
- Magnetic Field Structure and Power Spectrum
Zusammenfassung der Kapitel (Chapter Summaries)
The paper begins with an introduction that discusses the importance of understanding magnetic fields in galaxy clusters, their properties, and the various theories about their origin. Chapter 1 delves into the formation and general properties of galaxy clusters, including the intracluster medium (ICM), and the theories behind the origin of cluster magnetic fields, such as the primordial, protogalactic, and galactic scenarios. The methods used to measure these magnetic fields, including synchrotron radiation, inverse Compton effect, Faraday rotation maps, and their limitations, are also discussed. Chapter 2 presents the theoretical framework used in the simulations, covering concepts like the Friedman equation, comoving coordinates, the Poisson equation, and magnetohydrodynamics (MHD) equations. Chapter 3 details the simulation methodology, including the initial conditions, cosmology, gravitational interactions, adaptive mesh refinement, hydrodynamics, and the evolution of the magnetic field. Finally, Chapter 4 presents the results of the simulations, focusing on the structure formation, magnetic field evolution, and the properties of the final cluster, such as the correlation between the density and magnetic field strength, the magnetic energy power spectrum, and rotation maps. The paper concludes with a summary and outlook, highlighting the main findings and future research directions.
Schlüsselwörter (Keywords)
This paper focuses on magnetic fields in galaxy clusters, their formation, evolution, and impact on cluster properties. Key concepts include the intracluster medium (ICM), magnetohydrodynamics (MHD), adaptive mesh refinement simulations, magnetic field amplification, correlation with gas density, magnetic energy power spectrum, and Faraday rotation maps.
- Quote paper
- Aurora Simionescu (Author), 2005, Magnetic Fields in Galaxy Clusters, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/90115
