Lazarevic et al. report the discovery of a bow-shock pulsar wind nebula (PWN), dubbed Thunder, powered by the radio pulsar PSR J1631−4722 and projected within the Galactic supernova remnant (SNR) G336.7+0.5 (Nimbus). The system was first identified ASKAP observations for the Evolutionary Map of the Universe (EMU) survey and further characterised using MeerKAT Galactic Plane Survey data and follow-up ATCA observations at 5.5 and 9 GHz. The pulsar has a spin period of P = 118.7 ms and a characteristic age of ~34,000 years.  These properties indicate that PSR J1631−4722 is sufficiently energetic to power the observed PWN. The confined morphology of the nebula suggests that Thunder belongs to the small but growing class of bow-shock PWNe produced by supersonic pulsars moving through the inter-stellar medium.

Radio continuum images of the Pulsar Wind Nebula “Thunder” are shown above. Panels show (a) ASKAP 944 MHz, (b) MeerKAT 1284 MHz, (c) ASKAP 1367 MHz, (d) ATCA 5500 MHz, (e) ATCA 9000 MHz, (f) ATCA 9000 MHz. All images were produced using Briggs weighting with robust parameter of −0.5, except panel (f) where robust of −2 was used, to obtain the smallest angular resolution. The synthesised beam for each observation is shown as a white ellipse in the lower-left corner. The position of PSR J1631−4722, as inferred from pulsar timing, is indicated by the black cross. The apparent offset between the timing position and the radio peak is likely to be due to the fact that young pulsars such as PSR J1631−4722 display strong timing noise on timescales from months to years, which can make it difficult to obtain a reliable timing position with a relatively short observing baseline.