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

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 Ka 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 ratios; 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 ∼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.

Dusty Supernovae Running the Thermodynamics of the Matter Reinserted Within Young and Massive Super Stellar Clusters

“…Notable cases are those of the SN 1987A (see Moseley et al 1989;Matsuura et al 2011), the Crab Nebula (Gomez et al 2012), Cas A (Hines et al 2004), as well as the undecided type Kepler SN (see Reynolds et al 2007;, leading in all cases to dust masses, M d , of the order of several tenths to a few solar masses. The implication is that the condensation of refractory elements into dust is very efficient in the ejecta of core-collapse SNe.…”

Dynamical Evolution and Radiative Processes of Supernova Remnants

“…(See, for example, Winkler et al 2014for SN 1006and Hammell & Fesen 2008 for Cas A.) Radiative knots in the interior of Kepler's SNR (CE 1604) may be CSM, but some knots ahead of the blast wave are ejecta (Reynolds et al 2007). As the 56 Ni synthesized in a CC explosion decays, its decay products will heat local material which will then expand into cooler ejecta (the "nickel bubble" effect; Li et al 1993).…”

“…For a red supergiant (RSG) progenitor, the pre-explosion spectrum includes relatively little ionizing radiation, but the shock breakout of the RSG envelope will produce a UV flash that can ionize all the surrounding material (normally the RSG wind) out to a distance that can be many pc. A compact progenitor that has lost most of its envelope would not produce such a UV flash, but would have had a much stronger pre-explosion ionizing flux (Reynolds et al 2007).…”

Supernova remnants, planetary nebulae and superbubbles: Prospects for new XMM‐Newton observations

“…While Tycho's SNR is the prototype of a type Ia SN, Kepler's SNR is probably a type Ia as well, but with substantial circumstellar material (Reynolds et al 2007). In both remnants, a radial onion elemental structure is roughly preserved with iron toward the inner region and silicon in the outer ones (Decourchelle et al 2001;Cassam-Chenaï et al 2004a).…”