Searching for high-redshift superclusters

"superclusters" of metal-line systems (thought to be associated with galaxies) at large redshift, analogous to the absorbers found in the field surrounding the southern pair Tol 1037/1038. The unique ability of QSO absorption lines to reveal modest columns of gas at high redshift allows a pencil-beam survey of interesting fields. By concentrating on QSOs with known, rich, metal-line absorption systems and searching catalogs for nearby QSOs lying behind the proposed clusters, we have identified a number of promising fields. Initial results from QSOs surrounding Q1303+308 support the BAL hypothesis for the absorption in this object. We show that further observations will be of substantial use in delineating the extent and overdensity of superclustering at redshifts z ~ 1-2.