Progenitors and Explosion Properties of Supernova Remnants Hosting Central Compact Objects: II. A Global Systematic Study with a Comparison to Nucleosynthesis Models

TL;DR

This systematic study of supernova remnants with Central Compact Objects uses X-ray data to analyze explosion properties and progenitors, revealing discrepancies with existing nucleosynthesis models and suggesting the need for more advanced physics in models.

Contribution

The paper provides a comprehensive analysis of SNRs with CCOs, comparing observed ejecta yields to models and highlighting the gaps in current nucleosynthesis predictions.

Findings

Most progenitors are low-mass ($$25 solar masses) stars.

Explosions generally have low energies (<10$^{51}$ ergs).

Current models do not match observed ejecta yields.

Abstract

Core-collapse explosions of massive stars leave behind neutron stars, with a known diversity that includes the "Central Compact Objects" (CCOs). Typified by the neutron star discovered near the centre of the Cas A supernova remnant (SNR), CCOs have been observed to shine only in X-rays. To address their supernova progenitors, we perform a systematic study of SNRs that contain a CCO and display X-ray emission from their shock-heated ejecta. We make use of X-ray data primarily using the Chandra X-ray observatory, complemented with XMM-Newton. This study uses a systematic approach to the analysis of each SNR aimed at addressing the supernova progenitor as well as the explosion properties (energy and ambient density). After fitting for the ejecta abundances estimated from a spatially resolved spectroscopic study, we compare the data to six nucleosynthesis models making predictions on supernova ejecta yields in core-collapse explosions. We find that the explosion models commonly used by the astrophysics community do not match the ejecta yields for any of the SNRs, suggesting additional physics, e.g. multi-dimensional explosion models or updated progenitor structures, are required. Overall we find low-mass ($\leq$25 solar masses) progenitors among the massive stars population and low-energy explosions ($<$10$^{51}$ ergs). We discuss degeneracies in our model fitting, particularly how altering the explosion energy affects the estimate of the progenitor mass. Our systematic study highlights the need for improving on the theoretical models for nucleosynthesis predictions as well as for sensitive, high-resolution spectroscopy observations to be acquired with next-generation X-ray missions.