X-ray Detection of PSR B1757−24 and its Nebular Tail

We report the first X-ray detection of the radio pulsar PSR B1757−24 using the Chandra X-ray Observatory. The image reveals point-source emission at the pulsar position, consistent with being magnetospheric emission from the pulsar. In addition, we detect a faint tail extending nearly 20 east of the pulsar, in the same direction and with comparable morphology to the pulsar’s well-studied radio tail. The Xray tail is unlikely to be emission left behind following the passage of the pulsar, but rather is probably from synchrotron-emitting pulsar wind particles having flow velocity ∼7000 km s. Assuming the point-source X-ray emission is magnetospheric, the observed X-ray tail represents only ∼0.01% of the pulsar’s spin-down luminosity, significantly lower than the analogous efficiencies of most known X-ray nebulae surrounding rotationpowered pulsars.