Ray emission from the nearby PSR B1133+16 and other old pulsars

We detected a nearby (d similar or equal to 360 pc), old (tau similar or equal to 5Myr) pulsar B1133 + 16 with Chandra. The observed pulsar's flux is (0.8 +/- 0.2) x 10(-14) ergs cm(-2) s(-1) in the 0.5-8 keV band. Because of the small number of counts detected, the spectrum can be described by various models. A power-law fit of the spectrum gives a photon index Gamma approximate to 2.5 and an isotropic luminosity of 1.4 x 10(29) ergs s(-1) in the 0.5-8 keV band, which is about 1.6 x 10(-3) of the spin-down power. E. The spectrum can also be fitted by a blackbody model with a temperature of approximate to 2.8 MK and a projected emitting area of similar to 500 m(2), possibly a hot polar cap. The X-ray properties of PSR B1133 + 16 are similar to those of other old pulsars observed in X-rays, particularly the drifting pulsar B0943 + 10.