Radio polarimetry signatures of strong magnetic turbulence in Supernova Remnants

Abstract

We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at $90^{\circ }$ to the conventional electric polarization direction. We find that isotropic strong turbulence will produce weakly polarized radio emission even in the absence of internal Faraday rotation. If anisotropy is imposed on the magnetic-field structure, the degree of polarization can be significantly increased, provided internal Faraday rotation is inefficient. Both for shock compression and a mixture with a homogeneous field, the increase in polarization degree goes along with a fairly precise alignment of the magnetic-polarization angle with the direction of the dominant magnetic-field component, implying tangential magnetic polarization at the rims in the case of shock compression. We compare our model with high-resolution radio polarimetry data of Tycho's remnant. Using the absence of internal Faraday rotation we find a soft limit for the amplitude of magnetic turbulence, $\delta B\lesssim 200\mu \mathrm{G}$. The data are compatible with a turbulent magnetic field superimposed on a radial large-scale field of similar amplitude, $\delta B\simeq B_0$. An alternative viable scenario involves anisotropic turbulence with stronger amplitudes in the radial direction, as was observed in recent MHD simulations of shocks propagating through a medium with significant density fluctuations.

ApJ in press

References in corpus (26)

• Faraday Rotation Measure Synthesis
• On the magnetic fields and particle acceleration in Cas A
• Fine Structures of Shock of SN 1006 with the Chandra Observation
• Cosmic Ray Acceleration at the Forward Shock in Tycho's Supernova Remnant: Evidence from Chandra X-ray Observations
• A Million-Second Chandra View of Cassiopeia A
• A Spatial and Spectral Study of Nonthermal Filaments in Historical Supernova Remnants: Observational Results with Chandra
• Chandra Detection of the Forward and Reverse Shocks in Cassiopeia-A
• Diffusive Shock Acceleration with Magnetic Amplification by Non-resonant Streaming Instability in SNRs
• Rayleigh-Taylor Instabilities in Young Supernova Remnants Undergoing Efficient Particle Acceleration
• Production of Magnetic Turbulence by Cosmic Rays Drifting Upstream of Supernova Remnant Shocks
• Growth of Magnetic Fields Induced by Turbulent Motions
• Nonlinear Diffusive Shock Acceleration with Magnetic Field Amplification
• Morphological evidence for azimuthal variations of the cosmic ray ion acceleration at the blast wave of SN 1006
• Modeling Bell's Non-resonant Cosmic Ray Instability
• The transport of cosmic rays in self-excited magnetic turbulence
• Radio Spectral Index Variations and Physical conditions in Kepler's Supernova Remnant
• The Expansion of the X-ray Remnant of Tycho's Supernova (SN1572)
• Efficiency of Nonlinear Particle Acceleration at Cosmic Structure Shocks
• Dots, clumps and filaments: the intermittent images of synchrotron emission in random magnetic fields of young supernova remnants
• The Evolution of Adiabatic Supernova Remnants in a Turbulent, Magnetized Medium
• Cosmic-ray Acceleration at Ultrarelativistic Shock Waves: Effects of a "Realistic" Magnetic Field Structure
• MHD Turbulence as a Foreground for CMB Studies
• X-ray Hotspot Flares and Implications for Cosmic Ray Acceleration and Magnetic Field amplification in Supernova Remnants
• The origin of non-thermal X-ray filaments and TeV emission in young SNRs
• Modern theory of Fermi acceleration: a new challenge to plasma physics
• Production of Neutrinos and Secondary Electrons in Cosmic Sources

Cited by in corpus (15)

• The microphysics of collisionless shock waves
• Discovery of TeV Gamma Ray Emission from Tycho's Supernova Remnant
• Electron Injection by Whistler Waves in Non-relativistic Shocks
• A Model of Polarized X-ray Emission from Twinkling Synchrotron Supernova Shells
• Magnetic fields in cosmic particle acceleration sources
• Acceleration of cosmic rays by young core-collapse supernova remnants
• Kinetic simulations of nonrelativistic perpendicular shocks of young supernova remnants. I. Electron shock-surfing acceleration
• Kinetic simulations of turbulent magnetic-field growth by streaming cosmic rays
• Aperiodic magnetic turbulence produced by relativistic ion beams
• Hard X-ray emission and ${}^{44}$Ti line features of Tycho Supernova Remnant
• Balmer filaments in Tycho's supernova remnant: an interplay between cosmic-ray and broad-neutral precursors
• Expectation on Observation of Supernova Remnants with the LHAASO Project
• New perspectives on the supernova remnant Puppis A based on a radio polarization study
• Radio polarization maps of shell-type SNRs II. Sedov models with evolution of turbulent magnetic field
• Radio polarization from runaway star bowshocks-I. The general case