2017ApJ...835..178S

We constrain the X-ray properties of the nearby (360 pc), old (5 Myr) pulsar B1133+16 with ∼100 ks effective exposure time by XMM-Newton. The observed pulsar flux in the 0.2-3 keV energy range is ∼10^–14 erg cm^–2 s^–1, which results in the recording of ∼600 source counts with the EPIC pn and MOS detectors. The X-ray radiation is dominated by nonthermal radiation and is well described by both a single power-law model (PL) and a sum of blackbody and power-law emission (BB+PL). The BB+PL model results in a spectral photon index Γ=2.4_–0.3^+0.4 and a nonthermal flux in the 0.2-3 keV energy range of (7±2)×10^–15 erg cm^–2 s^–1. The thermal emission is consistent with the blackbody emission from a small hot spot with a radius of R_pc~14_–5⁺⁷ m and a temperature of T_s=2.9_–0.4^+0.6 MK. Assuming that the hot spot corresponds to the polar cap of the pulsar, we can use the magnetic flux conservation law to estimate the magnetic field at the surface B_s~3.9×10¹⁴ G. The observations are in good agreement with the predictions of the partially screened gap model, which assumes the existence of small-scale surface magnetic field structures in the polar cap region.