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 $N_H=6.7(4.0,9.7)\times {10}^{21}$ cm⁻² and photon index $\Gamma =1.8(1.4,2.2)$. For a distance of 4 kpc, the unabsorbed luminosity between 0.5 and 8 keV is ${1.7}_{-0.3}^{+0.4}\times {10}^{32}$ 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 $3\sigma$ upper limit to the surface brightness of any X-ray PWN near the point source to be $3\times {10}^{-17}$ 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 ($\alpha \sim -0.7$), if continued to the X-ray without a break, predicts $L_X\left(nebula\right)\sim 1\times {10}^{33}$ 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.