A Large Scale Structure at Redshift 1.71 in the Lockman Hole
  We previously identified LH146, a diffuse X-ray source in the Lockman Hole,
as a galaxy cluster at redshift 1.753. The redshift was based on one
spectroscopic value, buttressed by seven additional photometric redshifts. We
here confirm the previous spectroscopic redshift and present concordant
spectroscopic redshifts for an additional eight galaxies. The average of these
nine redshifts is 1.714 +/- 0.012 (error on mean). Scrutiny of the galaxy
distribution in redshift and the plane of the sky shows that there are two
concentrations of galaxies near the X-ray source. In addition there are three
diffuse X-ray sources spread along the axis connecting the galaxy
concentrations. LH146 is one of these three and lies approximately at the
center of the two galaxy concentrations and the outer two diffuse X-ray
sources. We thus conclude that LH146 is at the redshift initially reported but
it is not a single virialized galaxy cluster as previously assumed. Rather it
appears to mark the approximate center of a larger region containing more
objects. For brevity we term all these objects and their alignments as large
scale structure. The exact nature of LH146 itself remains unclear.
