2008ApJ...679..664P

We present the results of a ∼230 ks long X-ray observation of the relativistic double-pulsar system PSR J0737-3039 obtained with the XMM-Newton satellite in 2006 October. We confirm the detection in X-rays of pulsed emission from PSR J0737-3039A (PSR A), mostly ascribed to a soft nonthermal power-law component (Γ∼3.3) with a 0.2-3 keV luminosity of ∼1.9x10³⁰ erg/s (assuming a distance of 500 pc). For the first time, pulsed X-ray emission from PSR J0737-3039B (PSR B) is also detected in part of the orbit. This emission, consistent with thermal radiation with temperature k_BT≃30 eV and a bolometric luminosity of ∼10³² erg/s, is likely powered by heating of PSR B's surface caused by PSR A's wind. A hotter (∼130 eV) and fainter (∼5x10²⁹ erg/s) thermal component, probably originating from backfalling particles heating polar caps of either PSR A or PSR B, is also required by the data. No signs of X-ray emission from a bow shock between PSR A's wind and the interstellar medium or PSR B's magnetosphere are present. The upper limit on the luminosity of such a shock component (∼10²⁹ erg/s) constrains the wind magnetization parameter σ_M of PSR A to values greater than 1.