X-ray mapping of the stellar wind in the binary PSR J2032+4127/MT91 213

TL;DR

This study uses X-ray observations over several years to analyze the stellar wind and pulsar wind interactions in the binary system PSR J2032+4127/MT91 213, revealing a clumpy wind structure and constraining pulsar wind properties.

Contribution

It provides the first detailed X-ray mapping of the stellar wind in this binary, constrains the pulsar wind Lorentz factor, and explores the wind's polar structure effects on X-ray emission.

Findings

Detected increased X-ray luminosity linked to shocked pulsar wind.

Inferred a clumpy stellar wind with an $r^{-2}$ density profile.

Constrained pulsar wind Lorentz factor to between 10^5 and 10^6.

Abstract

PSR J2032+4127 is a young and rapidly rotating pulsar on a highly eccentric orbit around the high-mass Be star MT91 213. X-ray monitoring of the binary system over a $\sim$4000 day period with Swift has revealed an increase of the X-ray luminosity which we attribute to the synchrotron emission of the shocked pulsar wind. We use Swift X-ray observations to infer a clumpy stellar wind with $r^{-2}$ density profile and constrain the Lorentz factor of the pulsar wind to $10^5<\gamma_w<10^6$. We investigate the effects of an axisymmetric stellar wind with polar gradient on the X-ray emission. Comparison of the X-ray light curve hundreds of days before and after the periastron can be used to explore the polar structure of the wind.