2001ApJ...546.1159K

The young pulsar PSR B0540-69 was one of the first targets observed with the Chandra X-Ray Observatory. The high angular resolution of Chandra allows us to resolve the compact nebula surrounding the pulsar. We have determined a position for PSR B0540-69 of R.A.=05^h40^m11{fs}221,decl.=-69°19'54".98 (J2000) with a 1 σ radial uncertainty of 0".7. Combining our measurements of the pulsar period with previous measurements covering a span of 12 years, we derive a braking index of 2.082±0.005 (95% confidence). The spectrum of the pulsed emission is consistent with a power law with a photon index of 1.83±0.13. The compact nebula has a softer spectrum with a photon index of 1.85-2.26.