Particle acceleration controlled by ambient density in the southwestern rim of RCW 86

Abstract

Particle acceleration physics at supernova remnant (SNR) shocks is one of the most intriguing problems in astrophysics. SNR RCW~86 provides a suitable environment for understanding the particle acceleration physics because one can extract the information of both accelerated particles and acceleration environment at the same regions through the bright X-ray emission. In this work, we study X-ray proper motions and spectral properties of the southwestern region of RCW~86. The proper motion velocities are found to be $\sim 300$--2000~km~s${}^{-1}$ at a distance of 2.8~kpc. We find two inward-moving filaments, which are more likely reflected shocks rather than reverse shocks. Based on the X-ray spectroscopy, we evaluate thermal parameters such as the ambient density and temperature, and non-thermal parameters such as the power-law flux and index. From the flux decrease in time of several non-thermal filaments, we estimate the magnetic field amplitudes to be $\sim 30$--100~$\mu$G. Gathering the physical parameters, we then investigate parameter correlations. We find that the synchrotron emission from thermal-dominated filaments is correlated with the ambient density $n_{\mathrm{e}}$ as $\text{(power-law flux)}\propto n_{\mathrm{e}}^{1.0\pm 0.2}$ and $\text{(power-law index)}\propto n_{\mathrm{e}}^{0.38\pm 0.10}$, not or only weakly with the shock velocity and shock obliquity. As an interpretation, we propose a shock-cloud interaction scenario, where locally enhanced magnetic turbulence levels have a great influence on local acceleration conditions.

20 pages, 20 figures, accepted for publication in ApJ

References in corpus (10)

• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Analytical solutions for energy spectra of electrons accelerated by nonrelativistic shock-waves in shell type supernova remnants
• Non linear particle acceleration at non-relativistic shock waves in the presence of self-generated turbulence
• Magnetic-Field Amplification in the Thin X-ray Rims of SN1006
• Systematic Study of Acceleration Efficiency in Young Supernova Remnants with Nonthermal X-ray Observations
• Spatial and Temporal Variations of the Chandra ACIS Particle-Induced Background and Development of a Spectral-Model Generation Tool
• NuSTAR observations of the supernova remnant RX J1713.7$-$3946
• Observational constraints on the maximum energies of accelerated particles in supernova remnants: low maximum energies and a large variety
• Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties
• A Systematic Study of the Thermal and Nonthermal Emission in the Supernova Remnant RCW 86 with Suzaku

Cited by in corpus (3)

• Kinematics of Supernova Remnants Using Multiepoch Maximum Likelihood Estimation: Chandra Observation of Cassiopeia A as an Example
• A new wideband radio polarization observation of the Supernova Remnant G315.4$-$2.3
• Magnetic-field Order in the Southwestern Rim of RCW 86 Constrained Using X-Ray Polarimetry