Spatially Resolved RGS Analysis of Kepler's Supernova Remnant

TL;DR

This study uses spatially resolved X-ray spectroscopy to analyze the circumstellar medium of Kepler's supernova remnant, revealing velocity structures that inform the nature of its progenitor system.

Contribution

It provides the first spatially resolved RGS analysis of Kepler's SNR, revealing detailed velocity information of the CSM and insights into the progenitor's movement.

Findings

CSM component is blue-shifted with velocities 0-500 km/s.

The northwest half of the remnant is blue-shifted, southeast half is red-shifted.

Results support a runaway AGB star scenario for the progenitor.

Abstract

The distribution and kinematics of the circumstellar medium (CSM) around a supernova remnant (SNR) tell us useful information about the explosion of its natal supernova (SN). Kepler's SNR, the remnant of SN1604, is widely regarded to be of Type Ia origin. Its shock is moving through a dense, asymmetric CSM. The presence of this dense gas suggests that its parent progenitor system consisted of a white dwarf and an asymptotic giant branch (AGB) star. In this paper, we analyze a new and long observation with the reflection grating spectrometers (RGS) on board the XMM-Newton satellite, spatially resolving the remnant emission in the cross-dispersion direction. We find that the CSM component is blue-shifted with velocities in the general range 0-500 km/s. We also derive information on the central bar structure and find that the northwest half is blue-shifted, while the southeast half is red-shifted. Our result is consistent with a picture proposed by previous studies, in which a "runaway" AGB star moved to the north-northwest and toward us in the line of sight, although it is acceptable for both single-degenerate and core-degenerate scenarios for the progenitor system.