The many sides of RCW 86: a type Ia supernova remnant evolving in its progenitor's wind bubble

TL;DR

This study combines X-ray observations and hydrodynamical simulations to analyze RCW 86, supporting its origin as a type Ia supernova from a single degenerate system exploding within a wind-blown cavity.

Contribution

It provides detailed plasma diagnostics and a comprehensive model linking the remnant's morphology and dynamics to a non-spherical wind cavity from a type Ia supernova.

Findings

Ejecta confined to an oblate shell of ~2 pc width

Spectral properties consistent with a type Ia supernova in a wind cavity

Hydrodynamical models reproduce observed remnant features

Abstract

We present the results of a detailed investigation of the Galactic supernova remnant RCW 86 using the XMM-Newton X-ray telescope. RCW 86 is the probable remnant of SN 185 A.D, a supernova that likely exploded inside a wind-blown cavity. We use the XMM-Newton Reflection Grating Spectrometer (RGS) to derive precise temperatures and ionization ages of the plasma, which are an indication of the interaction history of the remnant with the presumed cavity. We find that the spectra are well fitted by two non-equilibrium ionization models, which enables us to constrain the properties of the ejecta and interstellar matter plasma. Furthermore, we performed a principal component analysis on EPIC MOS and pn data to find regions with particular spectral properties. We present evidence that the shocked ejecta, emitting Fe-K and Si line emission, are confined to a shell of approximately 2 pc width with an oblate spheroidal morphology. Using detailed hydrodynamical simulations, we show that general dynamical and emission properties at different portions of the remnant can be well-reproduced by a type Ia supernova that exploded in a non-spherically symmetric wind-blown cavity. We also show that this cavity can be created using general wind properties for a single degenerate system. Our data and simulations provide further evidence that RCW 86 is indeed the remnant of SN 185, and is the likely result of a type Ia explosion of single degenerate origin.