Xmm-Newton X-Ray Detection of the High-Magnetic-Field Radio Pulsar PSR B1916+14

Using observations made with the XMM-Newton Observatory, we report the first X-ray detection of the high-magnetic-field radio pulsar PSR B1916+14. We show that the X-ray spectrum of the pulsar can be well fitted with an absorbed blackbody with temperature in the range of 0.08-0.23 keV, or a neutron-star hydrogen atmosphere model with best-fit effective temperature of ~0.10 keV, higher than expected from fast cooling models. The origin of the likely thermal emission is not well constrained by our short observation and is consistent with initial cooling or return-current heating. We found no pulsations in these data and set a 1σ upper limit on the pulsed fraction in the 0.1-2 keV band of ~0.7. Implications of these results for our understanding of the different observational properties of isolated neutron stars are discussed.