  We present the results of an adaptive optics survey for faint companions
among Galactic O-type star systems (V < 8) using the Advanced Electro-Optical
System (AEOS) 3.6-meter telescope on Haleakala. We surveyed these O star
systems in I-band, typically being able to detect a companion with a magnitude
difference of about 6 in the projected separation range of 0.5 to 1.0
arcseconds, and of about 9.5 in the range of 1.0 to 5.0 arcseconds. In the
course of the survey, we discovered 40 new companions among 31 of the 116
objects examined and made astrometric and differential magnitude measurements
of 24 additional known pairs, several of them being confirmation detections. We
present new astrometric orbits for two binaries, BU 1032AB (WDS 05387-0236; sig
Ori AB) and SEE 322 (WDS 17158-3344; HD 155889AB). We lack magnitude
differences for other filter bands, so it is difficult to determine physical
from line-of-sight companions, but we present empirical arguments for the
limiting magnitude difference where field contamination is significant.
