A candidate optical counterpart to the middle-aged gamma-ray pulsar PSR J1741-2054

TL;DR

This study used the VLT to identify a likely optical counterpart to the gamma-ray pulsar PSR J1741-2054, detected its bow-shock nebula, and found no large-scale optical emission from its pulsar wind nebula.

Contribution

First deep optical observations of PSR J1741-2054 with VLT, identifying a probable optical counterpart and analyzing the bow-shock nebula's displacement.

Findings

Detected a faint optical object consistent with the pulsar's position.

Observed the bow-shock nebula displaced by ~0.9 arcseconds, aligned with proper motion.

No large-scale optical emission from the pulsar wind nebula was found.

Abstract

We carried out deep optical observations of the middle-aged $\gamma$-ray pulsar PSR J1741-2054 with the Very Large Telescope (VLT). We identified two objects, of magnitudes $m_v=23.10\pm0.05$ and $m_v=25.32\pm0.08$, at positions consistent with the very accurate Chandra coordinates of the pulsar, the faintest of which is more likely to be its counterpart. From the VLT images we also detected the known bow-shock nebula around PSR J1741-2054. The nebula is displaced by $\sim 0\farcs9$ (at the $3\sigma$ confidence level) with respect to its position measured in archival data, showing that the shock propagates in the interstellar medium consistently with the pulsar proper motion. Finally, we could not find evidence of large-scale extended optical emission associated with the pulsar wind nebula detected by Chandra, down to a surface brightness limit of $\sim 28.1$ magnitudes arcsec$^{-2}$. Future observations are needed to confirm the optical identification of PSR J1741-2054 and characterise the spectrum of its counterpart.