2017/01/10 by Andrzej Szary, Janusz Gil, Bing Zhang +5 · 1 citation
Physics and Astronomy · #astro-ph.HE
paper · pdf · doi:10.3847/1538-4357/835/2/178
10 pages, 8 figuers, accepted for publication in ApJ
arxiv created 2017/01/10 · arxiv updated 2017/02/08
We constrain the X-ray properties of the nearby (360 \rm pc), old (5 \rm Myr) pulsar B1133+16 with ∼ 100 \rm ks effective exposure time by \it XMM-Newton. The observed pulsar flux in the 0.2-3 keV energy range is ∼ 10-14 \rm erg cm-2 \rm 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+0.4-0.3 and a nonthermal flux in the 0.2-3 keV energy range of (7± 2) × 10-15 \rm erg cm-2 \rm s-1. The thermal emission is consistent with the blackbody emission from a small hot spot with a radius of R\rm pc ≈ 14+7-5 \rm m and a temperature of T\rm s = 2.9+0.6-0.4 \rm 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\rm s ≈ 3.9 × 1014 \rm 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.