ChandraDetection of a Synchrotron Nebula around the Vela‐like Pulsar J1016−5857

We report on a 19 ks observation of the pulsar J1016-5857 with the Chandra X-Ray Observatory . This "Vela-like" pulsar has rotation period 107 ms, characteristic age 21 kyr, and spin-down power 2.6 × 10 36 ergs s -1 . A relatively bright, centrally peaked source of radius ≈25'' around the radio pulsar position has a spectrum that is well fitted by an absorbed power law with photon index 1.32 ± 0.25. We regard this as a newly identified pulsar wind nebula (PWN) that we designate PWN G284.0-1.8. We do not detect the pulsar as either a point X-ray source or a pulsed source in a 55 ks observation with the Rossi X-Ray Timing Explorer . The isotropic PWN luminosity is 3 × 10 32 ergs s -1 in the 2-10 keV range, for a distance of 3 kpc that is consistent with the measured neutral hydrogen column density. The unpulsed flux from the pulsar is less than 30% of the measured PWN flux. The brightest component of the PWN, near the pulsar, shows extended emission of size ~2'' that may indicate, by analogy with other young pulsars, the wind termination shock. In the Chandra image we also detect a very faint extended structure ≈1' × 2' in size that is highly asymmetric about the pulsar position. This structure is a good match in width and position angle to the tip of a "finger" of radio emission that appears to connect to the nearby supernova remnant G284.3-1.8, but we cannot characterize it further with the available data. There is a variable X-ray point source only 1 5 from the pulsar, which we identify using optical spectroscopy as an accreting binary.