XMM-Newton and Suzaku detection of an X-ray emitting shell around the pulsar wind nebula G54.1+0.3

TL;DR

This study used X-ray observations from XMM-Newton and Suzaku to detect a faint, diffuse shell around the PWN G54.1+0.3, providing insights into its evolutionary stage and physical properties.

Contribution

First detection of an X-ray emitting shell around G54.1+0.3, revealing its physical parameters and confirming theoretical models of PWN-SNR evolution.

Findings

Detected a faint diffuse X-ray emission surrounding G54.1+0.3

Estimated explosion energy and age of the SNR shell

Confirmed model predictions with observed shell and PWN positions

Abstract

Recent X-ray observations have proved to be very effective in detecting previously unknown supernova remnant shells around pulsar wind nebulae (PWNe), and in these cases the characteristics of the shell provide further clues on the evolutionary stage of the embedded PWN. However, it is not clear why some PWNe are still "naked". We carried out an X-ray observational campaign targeted at the PWN G54.1+0.3, the "close cousin" of the Crab, with the aim to detect the associated SNR shell. We analyzed an XMM-Newton and Suzaku observations of G54.1+0.3 and we model out the contribution of dust scattering halo. We detected an intrinsic faint diffuse X-ray emission surrounding a hard spectrum, which can be modeled either with a power-law (gamma= 2.9) or with a thermal plasma model (kT=2.0 keV.). If the shell is thermal, we derive an explosion energy E=0.5-1.6x10^51 erg, a pre-shock ISM density of 0.2 cm^-3 and an age of about 2000 yr. Using these results in the MHD model of PWN-SNR evolution, we obtain an excellent agreement between the predicted and observed location of the shell and PWN shock.