The helical jet of the Vela Pulsar
  We have studied the fascinating dynamics of the nearby Vela pulsar's nebula in a campaign comprising eleven 40ks observations with Chandra X-ray Observatory (CXO). The deepest yet images revealed the shape, structure, and motion of the 2-arcminute-long pulsar jet. We find that the jet's shape and dynamics are remarkably consistent with that of a steadily turning helix projected on the sky. We discuss possible implications of our results, including free precession of the neutron star and MHD instability scenarios. 
Martin Durant, Oleg Kargaltsev, George G. Pavlov, Julia Kropotina,   Kseniya Levenfish
astro-ph.HE gr-qc hep-th