2011ApJ...730....2P

PSR B1259-63 is a middle-aged radio pulsar (P = 48 ms, τ = 330 kyr, and {dot}E=8.3×10^{35} erg/s) in an eccentric binary (P_orb= 3.4 yr, e = 0.87) with a high-mass Be companion, SS 2883. We observed the binary near apastron with the Chandra ACIS detector on 2009 May 14 for 28 ks. In addition to the previously studied point-like source at the pulsar's position, we detected extended emission on the south-southwest side of this source. The point-like source spectrum can be described by the absorbed power-law model with the hydrogen column density N_H= (2.5±0.6)x10²¹/cm2, photon index Γ = 1.6±0.1, and luminosity L_0.5-8 keV_~ 1.3x10³³ d ²₃ erg/s, where d₃ is the distance scaled to 3 kpc. This emission likely includes an unresolved part of the pulsar wind nebula (PWN) created by the colliding winds from the pulsar and the Be companion, and a contribution from the pulsar magnetosphere. The extended emission apparently consists of two components. The highly significant compact component looks like a southward extension of the point-like source image, seen up to ∼4'' from the pulsar position. Its spectrum has about the same slope as the point-like source spectrum, while its luminosity is a factor of 10 lower. We also detected an elongated feature extended ∼15'' southwest of the pulsar, but the significance of this detection is marginal. We tentatively interpret the resolved compact PWN component as a shocked pulsar wind blown out of the binary by the wind of the Be component, while the elongated component could be a pulsar jet.