A Deep Chandra Observation of Kepler's Supernova Remnant: A Type Ia Event with Circumstellar Interaction

TL;DR

This study uses a deep Chandra X-ray observation to analyze Kepler's supernova remnant, revealing evidence of a Type Ia supernova with circumstellar interaction and detailed ejecta composition.

Contribution

It provides detailed spectral analysis of over 100 regions, identifying different emission types and evidence of circumstellar interaction in Kepler's supernova remnant.

Findings

Majority show Fe and Si/S emission from shocked ejecta

Some regions show solar O/Fe ratios indicating shocked circumstellar medium

No central point source detected, constraining the remnant's compact object presence

Abstract

We present initial results of a 750 ks Chandra observation of the remnant of Kepler's supernova of AD 1604. The strength and prominence of iron emission, together with the absence of O-rich ejecta, demonstrate that Kepler resulted from a thermonuclear supernova, even though evidence for circumstellar interaction is also strong. We have analyzed spectra of over 100 small regions, and find that they fall into three classes. (1) The vast majority show Fe L emission between 0.7 and 1 keV and Si and S K alpha emission; we associate these with shocked ejecta. A few of these are found at or beyond the mean blast wave radius. (2) A very few regions show solar O/Fe abundance rations; these we associate with shocked circumstellar medium (CSM). Otherwise O is scarce. (3) A few regions are dominated by continuum, probably synchrotron radiation. Finally, we find no central point source, with a limit about 100 times fainter than the central object in Cas A. The evidence that the blast wave is interacting with CSM may indicate a Ia explosion in a more massive progenitor.