X-rays from the Power Sources of the Cepheus A Star-Forming Region
  We report an observation of X-ray emission from the exciting region of
Cepheus A with the Chandra/ACIS instrument. What had been an unresolved X-ray
source comprising the putative power sources is now resolved into at least 3
point-like sources, each with similar X-ray properties and differing radio and
submillimeter properties. The sources are HW9, HW3c, and a new source that is
undetected at other wavelengths "h10." They each have inferred X-ray
luminosities >= 10^31 erg s^-1 with hard spectra, T >= 10^7 K, and high
low-energy absorption equivalent to tens to as much as a hundred magnitudes of
visual absorption. The star usually assumed to be the most massive and
energetic, HW2, is not detected with an upper limit about 7 times lower than
the detections. The X-rays may arise via thermal bremsstrahlung in diffuse
emission regions associated with a gyrosynchrotron source for the radio
emission, or they could arise from powerful stellar winds. We also analyzed the
Spitzer/IRAC mid-IR observation from this star-formation region and present the
X-ray results and mid-IR classifications of the nearby stars. HH 168 is not as
underluminous in X-rays as previously reported.
