Evidence for Nonlinear Diffusive Shock Acceleration of Cosmic Rays in the 2006 Outburst of RS Ophiuchi

TL;DR

This paper presents evidence that nonlinear diffusive shock acceleration explains the observed deceleration and shock velocity differences in the 2006 RS Ophiuchi outburst, highlighting efficient particle acceleration at the blast wave.

Contribution

It demonstrates that nonlinear diffusive shock acceleration accounts for the blast wave deceleration and velocity discrepancies, extending understanding of particle acceleration in nova remnants.

Findings

Blast wave decelerates faster than standard models predict.

Nonlinear diffusive shock acceleration explains shock velocity differences.

Efficient particle acceleration occurs at the nova blast wave.

Abstract

Spectroscopic observations of the 2006 outburst of RS Oph at both infrared (IR) and X-ray wavelengths have shown that the blast wave has decelerated at a higher rate than predicted by the standard test-particle adiabatic shock-wave model. The observed blast-wave evolution can be explained, however, by the diffusive shock acceleration of particles at the forward shock and the subsequent escape of the highest energy ions from the acceleration region. Nonlinear particle acceleration can also account for the difference of shock velocities deduced from the IR and X-ray data. We discuss the evolution of the nova remnant in the light of efficient particle acceleration at the blast wave.