  We have detected significant X-ray emission from the direction of the young
radio pulsar PSR J1105-6107 using the ASCA Observatory. The 11 sigma detection
includes 460 background-subtracted source counts derived using data from all
four ASCA detectors. The emission shows no evidence of pulsations; the pulsed
fraction is less than 31%, at the 90% confidence level. The X-ray emission can
be characterized by a power-law spectrum with photon index alpha = 1.8 +/- 0.4,
for a neutral hydrogen column density Nh = 7 X 10E21 cm^-2. The unabsorbed 2 -
10 keV flux assuming the power-law model is (6.4 +/- 0.8) X 10E-13 ergs cm^-2
s^-1. The implied efficiency for conversion of spin-down luminosity to
ASCA-band emission is (1.6 +/- 0.2) X 10E-3, assuming a distance of 7 kpc to
the source. Within the limited statistics, the source is consistent with being
unresolved. We argue that the X-rays are best explained as originating from a
pulsar-powered synchrotron nebula.
