Phase-resolved spectroscopy of the vela pulsar with XMM-Newton

The similar to 10(4) yr old Vela Pulsar represents the bridge between the young Crab-like and the middle-aged rotation-powered pulsars. Its multiwavelength behavior is due to the superposition of different spectral components. We take advantage of the unprecedented harvest of photons collected by XMM-Newton to assess the Vela Pulsar spectral shape and to study the pulsar spectrum as a function of its rotational phase. As for the middle-aged pulsars Geminga, PSR B0656+14, and PSR B1055 - 52 ( the "Three Musketeers''), the phase-integrated spectrum of Vela is well described by a three-component model, consisting of two blackbodies ( T-bb = [1.06 +/- 0.03] x 10(6) K, R-bb = 5.1(-0.3)(+0.4) km, T-BB = 2.16(-0.07)(+0.06) x 10(6) K, R-BB = 0: 73(-0.07)(+0.09) km) plus a power law ( gamma = 2.2(-0.3)(+0.4)). The relative contributions of the three components are seen to vary as a function of the pulsar rotational phase. The two blackbodies have a shallow similar to 7%-9% modulation. The cooler blackbody, possibly related to the bulk of the neutron star surface, has a complex modulation, with two peaks per period, separated by similar to 0.35 in phase, the radio pulse occurring exactly in between. The hotter blackbody, possibly originating from a hot polar region, has a nearly sinusoidal modulation, with a single, broad maximum aligned with the second peak of the cooler blackbody, trailing the radio pulse by similar to 0.15 in phase. The nonthermal component, magnetospheric in origin, is present only during 20% of the pulsar phase and appears to be opposite to the radio pulse. XMM-Newton phase-resolved spectroscopy unveils the link between the thermally emitting surface of the neutron star and its charge-filled magnetosphere, probing emission geometry as a function of the pulsar rotation. This is a fundamental piece of information for future three-dimensional modeling of the pulsar magnetosphere.