NuSTAR and XMM-Newton Observations of PSR J1930+1852 and Its Pulsar Wind Nebula

TL;DR

This study combines NuSTAR and XMM-Newton observations to analyze the X-ray emission, spectrum, and particle acceleration in the pulsar wind nebula G54.1+0.3 and its central pulsar PSR J1930+1852, revealing spectral features and energy limits.

Contribution

It provides the first detailed broadband spectral analysis of PWN G54.1+0.3, including detection of high-energy emission and modeling of particle energy distribution.

Findings

X-ray emission detected up to 70 keV from the pulsar and PWN.

PWN spectrum fits a broken power law with a break at 5 keV.

Maximum particle energy estimated at ~400 TeV.

Abstract

Synchrotron X-ray emission from a pulsar wind nebula (PWN) is a sensitive probe of its magnetic field and high-energy particle population. Here we analyze contemporaneous NuSTAR and XMM-Newton observations of the PWN G54.1+0.3, powered by pulsar PSR J1930+1852. We also present a preliminary timing analysis of the central pulsar PSR J1930+1852 and analyze its X-ray pulse profiles in different energy bands. We detect X-ray emission from the combined pulsar and PWN system up to $\approx70$ keV, while emission from the PWN itself has been detected up to $\approx30$ keV, with a photon index $\Gamma$ increasing from $\sim 1.9$ to $\sim 2.4$ with photon energy between 3 and 30 keV. PWN G54.1+0.3's X-ray spectrum is consistent with a broken power law, with break energy $E_{\rm break} \approx 5$ keV, consistent with synchrotron cooling of a single power-law particle spectrum. The best-fit broadband spectral energy distribution model after the inclusion of this new spectral data indicates a maximum particle $E_{\rm max} \sim 400$ TeV. We discuss PSR J1930+1852 and PWN G54.1+0.3 in the context of other PWNe powered by young energetic pulsars.