Optical observations of PSR J1357-6429 field

TL;DR

This paper reports the detection of an optical counterpart to PSR J1357-6429 using VLT observations, revealing a steep spectrum and an exceptionally high pulsar velocity, contributing to understanding pulsar emission and dynamics.

Contribution

First optical identification of PSR J1357-6429 with detailed spectral analysis and velocity estimation, expanding knowledge of pulsar optical counterparts and their kinematic properties.

Findings

Detected optical counterpart consistent with X-ray position

Optical spectrum is unusually steep with spectral index ~5

Pulsar transverse velocity estimated at 1600-2000 km/s

Abstract

PSR J1357-6429 is a Vela-like radio pulsar that has been recently detected with Chandra and Fermi, which, like Vela, powers a compact X-ray pulsar wind nebula and X-ray-radio plerion associated with an extended TeV source. We present our deep optical observations with the Very Large Telescope to search for an optical counterpart of the pulsar and its nebula. We detected a point-like source in V, R, and I bands whose position is in agreement with the X-ray position of the pulsar, and whose colours are distinct from those of ordinary stars. The tentative optical luminosity and efficiency of the source are similar to those of the Vela pulsar, which also supports the optical identification. However, the source spectrum is unusually steep, with a spectral index of about 5, which is not typical of optical pulsars. The source offset from the radio position of PSR J1357-6429, which is in line with the corresponding offset of the X-ray position, implies the pulsar transverse velocity of 1600-2000 km/s at the distance of 2-2.5 kpc, making it the fastest moving pulsar known.