X-ray counterpart candidates for six new $\gamma$-ray pulsars

Abstract

Using archival X-ray data we have found point-like X-ray counterpart candidates positionally coincident with six $\gamma$-ray pulsars discovered recently in the Fermi Gamma-ray Space Telescope data by the Einstein@Home project. The candidates for PSRs J0002$+$6216, J0554$+$3107, J1844$-$0346 and J1105$-$6037 are detected with Swift, and those for PSRs J0359$+$5414 and J2017$+$3625 are detected with Chandra. Despite a low count statistics for some candidates, assuming plausible constraints on the absorbing column density towards the pulsars, we show that X-ray spectral properties for all of them are consistent with those observed for other pulsars. J0359$+$5414 is the most reliably identified object. We detect a nebula around it, whose spectrum and extent suggest that this is a pulsar wind nebula powered by the pulsar. Associations of J0002$+$6216 and J1844$-$0346 with supernova remnants CTB 1 and G28.6$-$0.1 are proposed.