XMM-Newton Observation of the Nearby Pulsar B1133+16

We constrain the X-ray properties of the nearby $\left(360pc\right)$, old ($5Myr$) pulsar B1133+16 with $\sim 100ks$ effective exposure time by XMM-Newton. The observed pulsar flux in the 0.2–3 keV energy range is $\sim {10}^{-14}erg{cm}^{-2}{s}^{-1}$, 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 $\Gamma ={2.4}_{-0.3}^{+0.4}$ and a nonthermal flux in the 0.2–3 keV energy range of $(7\pm 2)\times {10}^{-15}erg{cm}^{-2}{s}^{-1}$. The thermal emission is consistent with the blackbody emission from a small hot spot with a radius of $R_{pc}\approx {14}_{-5}^{+7}m$ 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 $B_s\approx 3.9\times {10}^{14}G$. 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.