Evidence for Surface Cooling Emission in theXMM‐NewtonSpectrum of the X‐Ray Pulsar PSR B2334+61

We report on the first XMM-Newton observation of the Vela-like pulsar PSRB2334+61. Spectral analysis reveals soft X-ray emission, with the bulk of thephotons emitted at energies below ~1.5 keV. We find that the spectrum has athermal origin and is well-fitted with either a blackbody or a magnetized, pureH atmospheric model. In the latter case, for a neutron star with a radius of 13km and a magnetic field of 10e13 G, the best-fit gives an hydrogen columndensity nH = 0.33 x 10^22 cm^-2 and an effective temperature T_eff^infinity =0.65 x 10^6 K, as measured at Earth. A comparison of the surface temperature ofPSR B2334+61 obtained from this fit with cooling curves favor a medium massneutron star with M ~ 1.45 solar masses or M ~ 1.6 solar masses, depending ontwo different models of proton superfluidity in the interior. We do not detectany pulsed emission from the source, and determine an upper limit of 5% for themodulation amplitude of the emission on the pulsar's radio frequency.Comment: 14 pages, 1 figure, 1 table, accepted for publication in Ap