  We present photometric and spectroscopic observations of the X-ray sources
detected in the wide-area, moderately deep Chandra Large Area Synoptic X-ray
Survey of the Lockman Hole-Northwest field. We have B, V, R, I, and z'
photometry for 521 (99%) of the 525 sources in the X-ray catalog and
spectroscopic redshifts for 271 (52%), including 20 stars. We do not find
evidence for redshift groupings of the X-ray sources, like those found in the
Chandra Deep Field surveys, because of the larger solid angle covered by this
survey. We separate the X-ray sources by optical spectral type and examine the
colors, apparent and absolute magnitudes, and redshift distributions for the
broad-line and non-broad-line active galactic nuclei. Combining our wide-area
survey with other Chandra and XMM-Newton hard X-ray surveys, we find a definite
lack of luminous, high accretion rate sources at z<1, consistent with previous
observations that showed that supermassive black hole growth is dominated at
low redshifts by sources with low accretion rates.

Astrophysics