Towards an X-ray inventory of nearby neutron stars

Abstract

The X-ray emission of neutron stars enables a probe of their temperatures, geometries, and magnetospheric properties. The current number of X-ray emitting pulsars is insufficient to rule out observational biases that may arise from poorly known distance, age, or location of the neutron stars. One approach to overcome such biases is to create a distance-limited sample with sufficiently deep observations. With the aim of better sampling of the nearby ($\lesssim$ 2kpc) neutron stars population, we started an XMM-Newton survey of pulsars to measure their X-ray fluxes or derive respective constraining upper limits. We investigated 14 nearby pulsars for potential X-ray counterparts using different energy bands and detectors. In addition to our new XMM-Newton data, we also considered archival data and catalogs. We discuss source properties and also check for alternative counterparts to the X-ray sources. In our new XMM-Newton data, we found two pulsar counterpart candidates with significance above over $4\sigma$ and one candidate with $3.5\sigma$ by combining EPIC camera detection likelihoods. We also report the detection of potential X-ray counterparts to 8 radio pulsars in the 4XMM-DR10 catalog which have not been reported in the literature.