Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop I: Shock Properties

Abstract

We have obtained a contiguous set of long-slit spectra of a shock wave in the Cygnus Loop to investigate its structure, which is far from the morphology predicted by 1D models. Proper motions from Hubble Space Telescope images combined with the known distance to the Cygnus Loop provide an accurate shock speed. Earlier analyses of shock spectra estimated the shock speed, postshock density, temperature, and elemental abundances. In this paper we determine several more shock parameters: a more accurate shock speed, ram pressure, density, compression ratio, dust destruction efficiency, magnetic field strength, and vorticity in the cooling region. From the derived shock properties we estimate the emissivities of synchrotron emission in the radio and pion decay emission in the gamma rays. Both are consistent with the observations if we assume simple adiabatic compression of ambient cosmic rays as in the van der Laan mechanism. We also find that, although the morphology is far from that predicted by 1D models and the line ratios vary dramatically from point to point, the average spectrum is matched reasonably well by 1D shock models with the shock speed derived from the measured proper motion. A subsequent paper will analyze the development of turbulence in the cooling zone behind the shock.

References in corpus (30)

• The MAPPINGS III Library of Fast Radiative Shock Models
• Simulations of Ion Acceleration at Non-relativistic Shocks. I. Acceleration Efficiency
• The Density Probability Distribution in Compressible Isothermal Turbulence: Solenoidal versus Compressive Forcing
• A Three-Dimensional Map of Milky-Way Dust
• CHIANTI - An atomic database for Emission Lines. Version 8
• A Unified Model for Galactic Discs: Star Formation, Turbulence Driving, and Mass Transport
• Balmer-Dominated Spectra of Nonradiative Shocks in the Cygnus Loop, RCW 86 and Tycho Supernova Remnants
• Observational signatures of particle acceleration in supernova remnants
• Is Turbulence in the Interstellar Medium Driven by Feedback or Gravity? An Observational Test
• Characterizing Magnetohydrodynamic Turbulence in the Small Magellanic Cloud
• Destruction of Interstellar Dust in Evolving Supernova Remnant Shock Waves
• Binospec: A Wide-field Imaging Spectrograph for the MMT
• On the Amplification of Magnetic Field by a Supernova Blast Shock Wave in a Turbulent Medium
• Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant
• Diffusive Shock Re-Acceleration
• The Turbulence Power Spectrum in Optically Thick Interstellar Clouds
• The Turbulence Velocity Power Spectrum of Neutral Hydrogen in the Small Magellanic Cloud
• Binospec Software System
• Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456
• Star formation from dense shocked regions in supersonic isothermal magneto-turbulence
• The Cygnus Loop's Distance, Properties, and Environment Driven Morphology
• Shock Speed, Cosmic Ray Pressure, and Gas Temperature in the Cygnus Loop
• Shell Shock and Cloud Shock: Results from Spatially-Resolved X-ray Spectroscopy with Chandra in the Cygnus Loop
• Forbidden Iron Lines and Dust Destruction in Supernova Remnant Shocks: The Case of N49 in the Large Magellanic Cloud
• Magnetic field amplification in supernova remnants
• Deep optical observations of G 65.3+5.7
• Chandra Observations of the Northeastern Rim of the Cygnus Loop
• Carbon, Helium and Proton Kinetic Temperatures in a Cygnus Loop Shock Wave
• Dense Regions in Supersonic Isothermal Turbulence
• Spitzer IRS Observations of the XA Region in the Cygnus Loop Supernova Remnant

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• SRG/eROSITA discovery of a radio faint X-ray candidate supernova remnant SRGe J003602.3+605421=G121.1-1.9
• The spectrum of magnetized turbulence in the interstellar medium
• Multiple accelerated particle populations in the Cygnus Loop with Fermi-LAT
• The double signature of local cosmic-ray acceleration in star-forming regions
• He abundance of Dense Circumstellar Clumps in the Cassiopeia A Supernova Remnant
• New continuum and polarization observations of the Cygnus Loop with FAST II. Images and analyses
• Imagery and UV Spectroscopy of the LMC Supernova Remnant N103B Using HST
• The Black Hole Candidate Swift J1728.9$-$3613 and the Supernova Remnant G351.9$-$0.9
• Self-generated ultraviolet radiation in molecular shock waves I. Effects of Lyman $\alpha$, Lyman $\beta$, and two-photon continuum
• Diagnosing Turbulence in the Neutral and Molecular Interstellar Medium of Galaxies