An extended X-ray object ejected from the PSR B1259-63/LS 2883 binary

TL;DR

This study analyzes Chandra X-ray data of the PSR B1259-63/LS 2883 binary, revealing a moving plasma clump ejected during periastron, providing insights into pulsar wind interactions and plasma acceleration.

Contribution

It presents the first detailed observation of an extended X-ray feature moving away from the binary, interpreted as a plasma clump accelerated by the pulsar wind.

Findings

The X-ray feature moves at about 0.07c with possible acceleration.

The spectrum remains hard with a photon index of 0.8.

The clump is likely ejected during periastron and interacts with the pulsar wind.

Abstract

We present the analysis of the Chandra X-ray Observatory observations of the eccentric gamma-ray binary PSR B1259-63/LS 2883. The analysis shows that the extended X-ray feature seen in previous observations is still moving away from the binary with an average projected velocity of about 0.07c and shows a hint of acceleration. The spectrum of the feature appears to be hard (photon index of 0.8) with no sign of softening compared to previously measured values. We interpret it as a clump of plasma ejected from the binary through the interaction of the pulsar with the decretion disk of the O-star around periastron passage. We suggest that the clump is moving in the unshocked relativistic pulsar wind (PW), which can accelerate the clump. Its X-ray emission can be interpreted as synchrotron radiation of the PW shocked by the collision with the clump.