Analysis of XMM-Newton Observations of Supernova Remnant W49B and Clues to the Progenitor

Abstract

W49B is a supernova remnant (SNR) discovered over 60 years ago in early radio surveys. It has since been observed over the entire wavelength range, with the X-ray morphology resembling a centrallyfilled SNR. The nature of its progenitor star is still debated. Applying Smoothed Particle Inference techniques to analyze the X-Ray emission from W49B, we characterize the morphology and abundance distribution over the entire remnant. We also infer the density structure and derive the mass of individual elements present in the plasma. The morphology is consistent with an interaction between the remnant and a dense medium along the eastern edge, and some obstruction towards the west. We find a total mass of 130 (±16) M and an estimated ejecta mass of 1.2 (±0.2) M . Comparison of the inferred abundance values and individual element masses with a wide selection of SN models suggests that deflagration-to-detonation (DDT) Type Ia models are the most compatible, with Fe abundance being the major discriminating factor. The general agreement between our abundance measurements and those from previous studies suggests that disagreement between various authors is more likely due to the choice of models used for comparison, rather than the abundance values themselves. While our abundance results lean toward a Type Ia origin, ambiguities in the interpretation of various morphological and spectral characteristics of W49B do not allow us to provide a definitive classification.

An Exploration of X-ray Supernova Remnants in the Milky Way and Nearby Galaxies

“…Although its age range is large, and thus its position is consistent with its age, the density appears to be higher than expected. W49B is known to be interacting with a dense cloud on one side, which could lead to an increase in X-ray emission, and thus a higher average value of the density (Zhou & Vink 2018;Siegel et al 2020 The estimated density at its position is consistent with the maximum density from the range of 2-5 cm −3 given by Leahy & Ranasinghe (2016).…”

“…It is not certain whether W49B is a Type Ia remnant or not. It was thought to be a core-collapse remnant for many years (Lopez et al 2013), but was recently classified as a Type Ia remnant by Zhou & Vink (2018), a designation supported by Siegel et al (2020). Although its age range is large, and thus its position is consistent with its age, the density appears to be higher than expected.…”

Supernova Archaeology in a Black-Hole Wind

“…Only a handful of elements can be measured in the limited visible band observed immediately after the explosion. Measuring abundances in SN remnants can reveal a few more elements, hint at the progenitor, and test SN models [16,17]. However, a full account of all elements dispersed by the SN has not been obtained from observations.…”