X-ray non-detection of PSR J0250 + 5854

We conducted a deep XMM$\unicode{x2013}$Newton observing campaign on the 23.5-s radio pulsar PSR J0250+5854 in order to better understand connection between long-period, radio-emitting neutron stars and their high-energy-emitting counterparts. No X-ray emission was detected resulting an upper limit bolometric luminosity of $<$10$^{31}$ erg s$^{-1}$ for assumed blackbody with temperature 85 eV, typical Dim Isolated Neutron Star (XDINS). compared known population XDINSs found that is lower than all but one XDINS. also SGR 0418+5729, magnetar low dipole magnetic field strength, where suggests if has thermal hot spot like it would have $<$200 320 eV magnetar.