PSR J1509–5850 is a middle-aged pulsar with the period P \approx 89 ms , spin-down power \dot { E } = 5.1 \times 10 ^ { 35 } erg s ^ { -1 } , at a distance of about 3.8 kpc .
We report on deep Chandra X-ray Observatory observations of this pulsar and its pulsar wind nebula ( PWN ) .
In addition to the previously detected tail extending up to 7 ^ { \prime } southwest from the pulsar ( the southern outflow ) , the deep images reveal a similarly long , faint diffuse emission stretched toward the north ( the northern outflow ) and the fine structure of the compact nebula ( CN ) in the pulsar vicinity .
The CN is resolved into two lateral tails and one axial tail pointing southwest ( a morphology remarkably similar to that of the Geminga PWN ) , which supports the assumption that the pulsar moves towards the northeast .
The luminosities of the southern and northern outflows are about 1 \times 10 ^ { 33 } and 4 \times 10 ^ { 32 } erg s ^ { -1 } , respectively .
The spectra extracted from four regions of the southern outflow do not show any softening with increasing distance from the pulsar .
The lack of synchrotron cooling suggests a high flow speed or in-situ acceleration of particles .
The spectra extracted from two regions of the northern outflow show a hint of softening with distance from the pulsar , which may indicate slower particle propagation .
We speculate that the northern outflow is associated with particle leakage from the bow shock apex into the ISM , while the southern outflow represents the tail of the shocked pulsar wind behind the moving pulsar .
We estimate the physical parameters of the observed outflows and compare the J1509–5850 PWN with PWNe of other supersonically moving pulsars .