Global enhancement and structure formation of the magnetic field in spiral galaxies

Abstract

We study numerically large-scale magnetic field evolution and its enhancement in gaseous disks of spiral galaxies. We consider a set of models with the various spiral pattern parameters and the initial magnetic field strength with taking into account gas self-gravity and cooling/heating. In agreement with previous studies, we find out that galactic magnetic field is mostly aligned with gaseous structures, however small-scale gaseous structures (spurs and clumps) are more chaotic than the magnetic field structure. In spiral arms magnetic field strongly coexists with the gas distribution, in the inter-arm region we see filamentary magnetic field structure. Simulations reveal the presence of the small-scale irregularities of the magnetic field as well as the reversal of magnetic field at the outer edge of the large-scale spurs. We provide evidences that the magnetic field in the spiral arms has a stronger mean-field component, and there is a clear inverse correlation between gas density and plasma-beta parameter, compared to the rest of the disk with a more turbulent component of the field and an absence of correlation between gas density and plasma-beta. We show the mean field growth up to 3-10$\mu G$ in the cold gas during several rotation periods (500-800 Myr), whereas ratio between azimuthal and radial field is equal to 4/1. Mean field strength increases by a factor of 1.5-2.5 for models with various spiral pattern parameters. Random magnetic field component can reach up to 25 % from the total strength. By making an analysis of the time-depended evolution of radial Poynting flux we point out that the magnetic field strength is enhanced stronger at the galactic outskirts which is due to the radial transfer of magnetic energy by the spiral arms pushing the magnetic field outward. Our results also support the presence of sufficient conditions for development of MRI at distances >11 kpc.

arXiv comment15 pages, 15 figures, accepted for publication in A&A

References in corpus (78)

• Astrophysical magnetic fields and nonlinear dynamo theory
• Origin of Galactic and Extragalactic Magnetic Fields
• The Star Formation Rate of Turbulent Magnetized Clouds: Comparing Theory, Simulations, and Observations
• A New Model of the Galactic Magnetic Field
• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
• Magnetic Fields in Spiral Galaxies
• Regulation of Star Formation Rates in Multiphase Galactic Disks: a Thermal/Dynamical Equilibrium Model
• Simulations of magnetic fields in isolated disk galaxies
• Strong magnetic fields in normal galaxies at high redshifts
• A new Jeans resolution criterion for (M)HD simulations of self-gravitating gas: Application to magnetic field amplification by gravity-driven turbulence
• Star Formation in Disk Galaxies. I. Formation and Evolution of Giant Molecular Clouds via Gravitational Instability and Cloud Collisions
• Modeling Molecular Hydrogen and Star Formation in Cosmological Simulations
• Clump morphology and evolution in MHD simulations of molecular cloud formation
• Pulsar rotation measures and the magnetic structure of our Galaxy
• Differential Rotation and Turbulence in Extended HI Disks
• CO-dark gas and molecular filaments in Milky Way type galaxies
• Mixing Time Scales in a Supernova-Driven Interstellar Medium
• Supernova Driving. I. The Origin of Molecular Cloud Turbulence
• A sub-parsec resolution simulation of the Milky Way: Global structure of the ISM and properties of molecular clouds
• The Exciting Lives of Giant Molecular Clouds
• Why are most molecular clouds not gravitationally bound?
• Implementing Molecular Hydrogen in Hydrodynamic Simulations of Galaxy Formation
• Formation and Fragmentation of Gaseous Spurs in Spiral Galaxies
• Magnetic fields in cosmological simulations of disk galaxies
• Direct simulations of a supernova-driven galactic dynamo
• Evolution of magnetic fields in galaxies and future observational tests with the Square Kilometre Array
• Magnetic fields in barred galaxies. IV. NGC 1097 and NGC 1365
• Magnetohydrodynamic Simulations of Disk Galaxy Formation: the Magnetization of The Cold and Warm Medium
• Formation of Spiral-Arm Spurs and Bound Clouds in Vertically Stratified Galactic Gas Disks
• The Pipe Nebula as seen with Herschel: Formation of filamentary structures by large-scale compression ?
• Instabilities of Spiral Shocks I: Onset of Wiggle Instability and its Mechanism
• Global galactic dynamo driven by cosmic-rays and exploding magnetized stars
• Global Modeling of Spur Formation in Spiral Galaxies
• The formation of molecular clouds in spiral galaxies
• Spurs and feathering in spiral galaxies
• Magnetic Field Amplification by Small-Scale Dynamo Action: Dependence on Turbulence Models and Reynolds and Prandtl Numbers
• The ISM in spiral galaxies: can cooling in spiral shocks produce molecular clouds?
• A small-scale dynamo in feedback-dominated galaxies as the origin of cosmic magnetic fields - I. The kinematic phase
• Two-Fluid MHD Simulations of Converging Hi Flows in the Interstellar Medium. II: Are Molecular Clouds Generated Directly from Warm Neutral Medium?
• The supernova-regulated ISM. II. The mean magnetic field
• The large-scale properties of simulated cosmological magnetic fields
• Magnetic field amplification during gravitational collapse - Influence of initial conditions on dynamo evolution and saturation
• Do Giant Molecular Clouds Care About the Galactic Structure?
• The alignment of molecular cloud magnetic fields with the spiral arms in M33
• Structure distribution and turbulence in self-consistently supernova-driven ISM of multiphase magnetized galactic discs
• Instabilities of Spiral Shocks -- II. A quasi-steady State in the multi-phase inhomogeneous ISM
• Galactic spiral patterns and dynamo action I: A new twist on magnetic arms
• Magnetised winds in dwarf galaxies
• Effects of simulated cosmological magnetic fields on the galaxy population
• Magnetic field structure due to the global velocity field in spiral galaxies
• 3D MHD Modeling of the Gaseous Structure of the Galaxy: Setup and Initial Results
• Nature of the Wiggle Instability of Galactic Spiral Shocks
• Magnetic fields and the dynamics of spiral galaxies
• Dynamo coefficients from local simulations of the turbulent ISM
• The simulation of molecular clouds formation in the Milky Way
• Multiscale magnetic fields in spiral galaxies: evolution and reversals
• Magnetic Spiral Arms and Galactic Outflows
• Magnetic and gaseous spiral arms in M83
• Toward a hybrid dynamo model for the Milky Way
• The relation between magnetic and material arms in models for spiral galaxies
• GMCs scaling relations: role of the cloud definition
• Numerical code for multi-component galaxies: from N-body to chemistry and magnetic fields
• What is a GMC? Are Observers and Simulators Discussing the Same Star-forming Clouds?
• The magnetic field structure of the central region in M31
• Magnetic field evolution and reversals in spiral galaxies
• Molecular cloud formation in high-shear, magnetized colliding flows
• Periodicity makes galactic shocks unstable - I. Linear analysis
• Magnetic field amplification and X-ray emission in galaxy minor mergers
• Do magnetic fields influence gas rotation in galaxies?
• The formation of regular interarm magnetic fields in spiral galaxies
• GMC Evolution in a Barred Spiral Galaxy with Star Formation and Thermal Feedback
• Magnetic field reversals and galactic dynamos
• Wiggle Instability of Galactic Spiral Shocks: Effects of Magnetic Fields
• Polygonal Structures in the Gaseous Disk: Numerical Simulations
• Influence of Ohmic diffusion on the excitation and dynamics of MRI
• Magnetic fields in ring galaxies
• Magnetic fields: Impact on the rotation curve of the Galaxy

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