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

Abstract

We carried out deep optical observations of the middle-aged γ-ray pulsar PSR J1741−2054 with the Very Large Telescope (VLT). We identified two objects, of magnitudes m v = 23.10±0.05 and m v = 25.32 ± 0.08, 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 ∼ 0. ′′ 9 (at the 3σ 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 ∼ 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.

DEEP OPTICAL OBSERVATIONS OF UNUSUAL NEUTRON STAR CALVERA WITH THE GTC∗

“…For the middle-aged RPPs detected in the optical and X-rays, the peak of the NS surface thermal emission usually exceeds the non-thermal background of the pulsar magnetosphere origin however the magnitude of the excess can be different. For instance, for PSR J1741−2054, whose optical counterpart candidate was recently detected (Mignani et al 2016), this excess is about one order of magnitude. The same situation probably occurs for PSR J1357−6429 (Zyuzin et al 2016, figure 3).…”

“…We also add the data on PSR J1741−2054. The X-ray luminosity is taken form Karpova et al (2014) and the optical one from Mignani et al (2016). For both bands, a factor of two uncertainty on the distance is taken into account (Karpova et al 2014;Mignani et al 2016).…”

“…The X-ray luminosity is taken form Karpova et al (2014) and the optical one from Mignani et al (2016). For both bands, a factor of two uncertainty on the distance is taken into account (Karpova et al 2014;Mignani et al 2016). Dashed lines correspond to different optical and X-ray efficiencies η V ≡ L V / Ė and η X ≡ L X / Ė.…”