Chandra Observations of the Anomalous X‐Ray Pulsar 4U 0142+61

Abstract

We present X-ray imaging, timing, and phase-resolved spectroscopy of the anomalous X-ray pulsar 4U 0142+61 using the Chandra X-Ray Observatory. The spectrum is well described by a power-law plus black-body model with Γ = 3.35(2), kTBB = 0.458(3) keV, and NH = 0.91(2) × 1022 cm-2; we find no significant evidence for spectral features (0.5-7.0 keV). Time-resolved X-ray spectroscopy shows evidence for evolution in phase in either Γ, kTBB, or some combination thereof as a function of pulse phase. We derive a precise X-ray position for the source and determine its spin period, P = 8.68866(30) s. We have detected emission beyond 4″ from the central source and extending beyond 100″, likely due to dust scattering in the interstellar medium.