Suzaku View of the Supernova Remnant RCW 86: X-Ray Studies of Newly-Discovered Fe-Rich Ejecta

TL;DR

This study uses Suzaku X-ray observations to map and analyze Fe-rich ejecta in the supernova remnant RCW 86, providing insights into its composition, structure, and likely Type Ia supernova origin.

Contribution

First comprehensive mapping of Fe-rich plasma distribution in RCW 86, revealing ejecta morphology and estimating ejecta mass, supporting a Type Ia supernova origin.

Findings

Fe-rich ejecta detected in multiple regions of RCW 86

Estimated ejecta mass of 1-2 solar masses

Evidence of Fe-rich clumps beyond the forward shock

Abstract

We report on results of imaging and spectral analysis of the supernova remnant (SNR) RCW 86 observed with Suzaku. The SNR is known to exhibit K-shell emission of low ionized Fe, possibly originating from supernova ejecta. We revealed the global distribution of the Fe-rich plasma in the entire remnant, for the first time; the Fe-K emission was clearly detected from the west, north, and south regions, in addition to the X-ray brighter shells of southwest and northeast, where the presence of the Fe-rich ejecta has already been reported. The spectrum of each region is well represented by a three-component model consisting of low- and high-temperature thermal plasmas and a non-thermal emission. The lower-temperature component, with elemental abundances of near the solar values, likely originates from the forward shocked interstellar medium, while the Fe-rich ejecta is described by the hotter plasma. From the morphologies of the forward and reverse shocks in the west region, the total ejecta mass is estimated to be 1-2M_sun for the typical explosion energy of ~ 1 x 10^{51} erg. The integrated flux of the Fe-K emission from the entire SNR roughly corresponds to a total Fe mass of about 1M_sun. Both of these estimates suggest a Type Ia supernova origin of this SNR. We also find possible evidence of an Fe-rich clump located beyond the forward-shock front in the north rim, which is reminiscent of ejecta knots observed in the Tycho and Vela SNRs.