A Compact X-Ray Source in the Radio Pulsar-wind Nebula G141.2+5.0

We report the results of a 50 ks Chandra observation of the recently discovered radio object G141.2+5.0, presumed to be a pulsar-wind nebula. We find a moderately bright unresolved X-ray source that we designate CXOU J033712.8 615302 coincident with the central peak radio emission. An absorbed power-law fit to the 241 counts describes the data well, with absorbing column {N}_H=6.7(4.0,9.7)× {10}²¹ cm^-2 and photon index {{Γ }}=1.8(1.4,2.2). For a distance of 4 kpc, the unabsorbed luminosity between 0.5 and 8 keV is {1.7}_-0.3^+0.4× {10}³² erg s^-1 (90% confidence intervals). Both L_X and Γ are quite typical of pulsars in PWNe. No extended emission is seen; we estimate a conservative 3σ upper limit to the surface brightness of any X-ray PWN near the point source to be 3× {10}^-17 erg cm^-2 s^-1 arcsec^-2 between 0.5 and 8 keV, assuming the same spectrum as the point source; for a nebula of diameter 13^\prime\prime , the flux limit is 6% of the flux of the point source. The steep radio spectrum of the PWN (α ∼ -0.7), if continued to the X-ray without a break, predicts {L}_{{X}} {{(nebula)}}∼ 1× {10}³³ erg s^-1, so additional spectral steepening between radio and X-rays is required, as is true of all known PWNe. The high Galactic latitude gives a z-distance of 350 pc above the Galactic plane, quite unusual for a Population I object.