XMM-Newton Observes the Intrabinary Shock of PSR J1959+2048

TL;DR

This study uses XMM-Newton observations to analyze the intrabinary shock in the black widow pulsar PSR J1959+2048, revealing orbital modulation, asymmetry, and eclipse features that inform system geometry and evolution.

Contribution

It provides the first detailed X-ray analysis of the intrabinary shock in PSR J1959+2048, including orbital modulation, asymmetry, and wind properties, enhancing understanding of black widow pulsar systems.

Findings

Orbital modulation caused by intrabinary shock emission observed.

Asymmetric IBS light curve suggests sweep-back effects in the companion wind.

Evidence for X-ray eclipse indicates high inclination and companion wind effects.

Abstract

In a multi-orbit (100 ks) $\mathrm{\it XMM-Newton}$ exposure of the original black widow pulsar, PSR J1959+2048, we measure the strong orbital modulation caused by intrabinary shock (IBS) emission. The IBS light curve peak appears asymmetric, which we attribute to sweep-back effects in the companion wind. We also see evidence for an X-ray eclipse by the companion and its wind. Together with the IBS fit, this supports an edge-on $i\sim 90^\circ$ view of the system and a modest $\sim 1.8M_\odot$ mass for the recycled pulsar. Our IBS fit parameters imply a wind flux that, if persistent, would evaporated the companion within a few Gyr.