Core-collapse model of broadband emission from SNR RX J1713.7-3946 with thermal X-rays and Gamma-rays from escaping cosmic rays

TL;DR

This paper develops a detailed spherically symmetric model of SNR RX J1713.7-3946, incorporating hydrodynamics and cosmic ray acceleration, to explain broadband emission including thermal X-rays and gamma-rays, and assesses different scenarios for the origin of high-energy emission.

Contribution

It introduces a comprehensive core-collapse supernova remnant model that couples hydrodynamics with nonlinear diffusive shock acceleration and cosmic ray escape, providing insights into the origin of broadband emission.

Findings

GeV-TeV emission is mainly inverse-Compton from CR electrons in isolated SNRs.

Pion-decay from escaping CRs could dominate TeV emission if interacting with large mass clouds, but is unlikely for RX J1713.7-3946.

CR ion production is crucial even in models dominated by leptonic processes.

Abstract

We present a spherically symmetric, core-collapse model of SNR RX J1713.7-3946 that includes a hydrodynamic simulation of the remnant evolution coupled to the efficient production of cosmic rays (CRs) by nonlinear diffusive shock acceleration (DSA). High-energy CRs that escape from the forward shock (FS) are propagated in surrounding dense material that simulates either a swept-up, pre-supernova shell or a nearby molecular cloud. The continuum emission from trapped and escaping CRs, along with the thermal X-ray emission from the shocked heated ISM behind the FS, integrated over the remnant, is compared against broadband observations. Our results show conclusively that, overall, the GeV-TeV emission is dominated by inverse-Compton from CR electrons if the supernova is isolated regardless of its type, i.e., not interacting with a >>100 Msun shell or cloud. If the SNR is interacting with a much larger mass >10^4 Msun, pion-decay from the escaping CRs may dominate the TeV emission, although a precise fit at high energy will depend on the still uncertain details of how the highest energy CRs are accelerated by, and escape from, the FS. Based on morphological and other constraints, we consider the 10^4 Msun pion-decay scenario highly unlikely for SNR RX J1713.7-3946 regardless of the details of CR escape. Importantly, even though CR electrons dominate the GeV-TeV emission, the efficient production of CR ions is an essential part of our leptonic model.