We conducted a deep XMM\unicodex2013Newton observing campaign on the 23.5-s radio pulsar PSR J0250+5854 in order to better understand the connection between long-period, radio-emitting neutron stars and their high-energy-emitting counterparts. No X-ray emission was detected resulting in an upper limit in the bolometric luminosity of PSR J0250+5854 of <1031 erg s−1 for an assumed blackbody with a temperature of 85 eV, typical of an X-ray Dim Isolated Neutron Star (XDINS). We compared the upper limit in the bolometric luminosity of PSR J0250+5854 with the known population of XDINSs and found that the upper limit is lower than the bolometric luminosity of all but one XDINS. We also compared PSR J0250+5854 with SGR 0418+5729, the magnetar with low dipole magnetic field strength, where the upper limit suggests that if PSR J0250+5854 has a thermal hot spot like SGR 0418+5729, it would have a blackbody temperature of <200 eV, compared to 320 eV of the magnetar.
@article{arxiv.2302.06490,
title = {X-ray nondetection of PSR J0250+5854},
author = {C. M. Tan and M. Rigoselli and P. Esposito and B. W. Stappers},
journal= {arXiv preprint arXiv:2302.06490},
year = {2023}
}