Magnetic fields in the nearby spiral galaxy IC 342: A multi-frequency radio polarization study

Abstract

The total and polarized radio continuum emission of IC 342 was observed in four wavelength bands with the Effelsberg and VLA telescopes. The frequency dependence of the radial scalelength of synchrotron emission indicates energy-dependent propagation of the cosmic-ray electrons, probably via the streaming instability. The equipartition strength of the total magnetic field is typically 15 muG, that of the ordered field 5 muG. Faraday rotation of the polarization angles reveals an underlying regular field of only about 0.5 muG strength with a large-scale axisymmetric spiral pattern, signature of a mean-field dynamo, and an about 10x stronger field that fluctuates on scales of a few 100 pc. The magnetic field around the bar in the central region of IC 342 resembles that of large barred galaxies; its regular spiral field is directed outwards, opposite to that in the disk. The polarized emission in the disk is concentrated in: (1) a narrow arm of about 300 pc width, displaced inwards with respect to the eastern arm by about 200 pc, indicating magnetic fields compressed by a density wave; (2) a broad arm of 300-500 pc width around the northern arm with systematic variations in polarized emission, polarization angles, and Faraday rotation measures on a scale of about 2 kpc, indicative of a helically twisted flux tube generated by the Parker instability; (3) a rudimentary "magnetic arm" in an interarm region in the north-west; (4) several broad spiral arms in the outer galaxy, related to spiral arms in the total neutral gas; (5) short features in the outer south-western galaxy, probably distorted by tidal interaction. - The generation and development of "magnetic arms" by a mean-field dynamo probably need a spiral pattern that is stable over a few galactic rotation periods. The dynamo in IC 342 is slow and weak, probably disturbed by the bar, tidal interaction, or a transient spiral pattern.

Accepted for publication in Astronomy & Astrophysics

References in corpus (32)

• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• What is Driving the HI Velocity Dispersion?
• Dawes Review 4: Spiral Structures in Disc Galaxies
• Magnetism in the spiral galaxy NGC 6946: magnetic arms, depolarization rings, dynamo modes and helical fields
• HI holes and high-velocity clouds in the spiral galaxy NGC 6946
• Direct simulations of a supernova-driven galactic dynamo
• Evolution of magnetic fields in galaxies and future observational tests with the Square Kilometre Array
• Galactic dynamo and helicity losses through fountain flow
• Global galactic dynamo driven by cosmic-rays and exploding magnetized stars
• The Blueshifting and Baldwin effects for the [OIII] 5007 Emission Line in Type 1 Active Galactic Nuclei
• Connecting Far-Infrared and Radio Morphologies of Disk Galaxies: Cosmic-Ray Electron Diffusion After Star Formation Episodes
• Galactic dynamos supported by magnetic helicity fluxes
• High-resolution radio continuum survey of M33 II. Thermal and nonthermal emission
• The nature of the low-frequency emission of M51: First observations of a nearby galaxy with LOFAR
• Lopsided Spiral Galaxies
• The supernova-regulated ISM. II. The mean magnetic field
• Winds, Clumps, and Interacting Cosmic Rays in M82
• The Radio Continuum-Star Formation Rate Relation in WSRT SINGS Galaxies
• Analysis of spiral arms using anisotropic wavelets: gas, dust and magnetic fields in M51
• High-resolution radio continuum survey of M33: III. Magnetic fields
• Magnetic Prandtl number dependence of kinetic to magnetic dissipation ratio
• Magnetic field structures of galaxies derived from analysis of Faraday rotation measures, and perspectives for the SKA
• Magnetic Fields in a Sample of Nearby Spiral Galaxies
• Magnetic fields and the dynamics of spiral galaxies
• Self-Regulated Fueling of Galaxy Centers: Evidence for Star-Formation Feedback in IC342's Nucleus
• Quantifying Resonant Structure in NGC 6946 from Two-dimensional Kinematics
• Magnetic Spiral Arms and Galactic Outflows
• Global simulations of the magnetic field evolution under the influence of the cosmic-ray-driven dynamo
• High resolution radio continuum survey of M33: I. The radio maps
• The magnetic field structure of the central region in M31
• Do magnetic fields influence gas rotation in galaxies?
• Magnetic fields near the peripheries of galactic discs

Cited by in corpus (49)

• The Radio Spectral Energy Distribution and Star Formation Rate Calibration in Galaxies
• Pulsar Rotation Measures and Large-scale Magnetic Field Reversals in the Galactic Disk
• MHD Turbulence
• Galactic Dynamos
• Introducing SPHINX-MHD: The Impact of Primordial Magnetic Fields on the First Galaxies, Reionization, and the Global 21cm Signal
• How primordial magnetic fields shrink galaxies
• A small-scale dynamo in feedback-dominated galaxies - III. Cosmological simulations
• Radiation-MagnetoHydrodynamics simulations of cosmic ray feedback in disc galaxies
• Seed magnetic fields in turbulent small-scale dynamos
• CHANG-ES XIII: Transport processes and the magnetic fields of NGC 4666 - indication of a reversing disk magnetic field
• Resolved magnetic structures in the disk-halo interface of NGC 628
• Magnetic fields in the Milky Way from pulsar observations: effect of the correlation between thermal electrons and magnetic fields
• Magnetization of the intergalactic medium in the IllustrisTNG simulations: the importance of extended, outflow-driven bubbles
• The NOD3 software package: A graphical user interface-supported reduction package for single-dish radio continuum and polarisation observations
• Simulations of cosmic ray propagation
• Unraveling the origin of magnetic fields in galaxies
• Cosmic Magnetism in Centimeter and Meter Wavelength Radio Astronomy
• Extragalactic Magnetism with SOFIA (Legacy Program) -- I: The magnetic field in the multi-phase interstellar medium of M51
• The Pandora project. I: the impact of radiation and cosmic rays on baryonic and dark matter properties of dwarf galaxies
• Polarimetric studies of magnetic turbulence with interferometer
• The radio continuum perspective on cosmic-ray transport in external galaxies
• CHANG-ES VIII: Uncovering Hidden AGN Activity in Radio Polarization
• The far-infrared - radio correlation in dwarf galaxies
• Magnetic Spiral Arms in Galaxy Halos
• Nearby galaxies in the LOFAR Two-metre Sky Survey II. The magnetic field-gas relation
• The formation of regular interarm magnetic fields in spiral galaxies
• Evolving Galactic Dynamos and Fits to the Reversing Rotation Measures in the Halo of NGC 4631
• Synchrotron Emission on FIRE: Equipartition Estimators of Magnetic Fields in Simulated Galaxies with Spectrally-Resolved Cosmic Rays
• Transition from small-scale to large-scale dynamo in a supernova-driven, multiphase medium
• Dwarf galaxies as a probe of a primordially magnetized Universe
• Magnetic fields in star-forming systems (II): examining dust polarization, the Zeeman effect, and the Faraday rotation measure as magnetic field tracers
• Steady states of the Parker instability
• A sensitive, high-resolution, wide-field IRAM NOEMA CO(1-0) survey of the very nearby spiral galaxy IC 342
• Inadequate turbulent support in low-metallicity molecular clouds
• Magnetic fields and cosmic rays in M31. II. Strength and distribution of the magnetic field components
• Understanding the radio luminosity function of star-forming galaxies and its cosmological evolution
• Magnetic Field Vector Structure of NGC6946
• Influence of Magnetic Fields on the Gas Rotation in the Galaxy $NGC6946$
• Low radio frequency observations of seven nearby galaxies with GMRT
• Radio-FIR correlation- A probe into cosmic ray propagation in the nearby galaxy IC 342
• Rotation measure and synchrotron emission signatures in simulations of magnetized galactic discs
• A new window into the sub-parsec scale magnetic field in the Milky Way? Unveiling small-scale magneto-ionic structures with Faraday complexity
• Investigation of the Radial Profile of Galactic Magnetic Fields using Rotation Measure of Background Quasars
• Probing the Morphology of Polarized Emission Induced by Fluctuation Dynamo using Minkowski Functionals
• Large-scale magnetic field structure of NGC 3627 based on magnetic vector map
• Towards convergence of turbulent dynamo amplification in cosmological simulations of galaxies
• Pseudo-observation of spiral galaxies in the radio band to verify depolarization models
• MeerKAT observations of the spiral galaxy NGC 2997 in the S band. Detection of high dynamo modes
• Non-Gaussian Magnetic Structures in the Small-Scale Turbulent Dynamo