HST multi-epoch imaging of the PSR B0540-69 system unveils a highly dynamic synchrotron nebula

TL;DR

This study uses a decade of Hubble Space Telescope imaging to reveal significant variability in the pulsar wind nebula of PSR B0540-69, including a hot spot moving at high speed, and sets an upper limit on the pulsar's proper motion.

Contribution

The paper provides the first long-term variability analysis of PSR B0540-69's nebula and constrains the pulsar's velocity using multi-epoch imaging data.

Findings

Detected a hot spot moving at ~0.04c in the nebula.

Observed significant nebula variability over 10 years.

Set an upper limit of 290 km/s on pulsar proper motion.

Abstract

PSR B0540-69 is the Crab twin in the Large Magellanic Cloud. Age, energetic and overall behaviour of the two pulsars are very similar. The same is true for the general appearance of their pulsar wind nebulae (PWNe). Analysis of Hubble Space Telescope images spanning 10 years unveiled significant variability in the PWN surrounding PSR B0540-69, with a hot spot moving at ~0.04c. Such behaviour, reminiscent of the variability observed in the Crab nebula along the counter-jet direction, may suggest an alternative scenario for the geometry of the system. The same data were used to assess the pulsar proper motion. The null displacement recorded over 10 y allowed us to set a 3sigma upper limit of 290 km/s to the pulsar velocity.