We report the first detection of pulsed X-ray emission from the young,
energetic radio and Gamma-ray pulsar PSR B1706-44. We find a periodic signal at
a frequency of f = 9.7588088 +/- 0.0000026 Hz (at epoch 51585.34104 MJD),
consistent with the radio ephemeris, using data obtained with the High
Resolution Camera on-board the Chandra X-ray Observatory}. The probability that
this detection is a chance occurrence is 3.5E-5 as judged by the Rayleigh test.
The folded light curve has a broad, single-peaked profile with a pulsed
fraction of 23% +/- 6%. This result is consistent the ROSAT PSPC upper limit of
< 18% after allowing for the ability of Chandra to resolve the pulsar from a
surrounding synchrotron nebula. We also fitted Chandra spectroscopic data on
PSR B1706-44, which require at least two components, e.g., a blackbody of
temperature T(infinity) between 1.51E6 K and 1.83E6 K and a power-law of Gamma
= 2.0 +/- 0.5. The blackbody radius at the nominal 2.5 kpc distance is only
R(infinity) = 3.6 +/- 0.9 km, indicating either a hot region on a cooler
surface, or the need for a realistic atmosphere model that would allow a lower
temperature and larger area. Because the power-law and blackbody spectra each
contribute more than 23% of the observed flux, it is not possible to decide
which component is responsible for the modulation in the spectrally unresolved
light curve.Comment: 6 pages, 4 figures, Latex, emulateapj. Published version. Includes an
updated radio ephemeris and presents the absolute radio/X-ray phase alignmen