Thesis Supervisor: Michael West
Abstract
Relatively few clusters of galaxies are known at redshifts z > 1. This is because methods that work well for finding clusters at lower redshifts - like detection of x-ray emission from hot intracluster gas or optical imaging - become inefficient for detecting more distant clusters. To find the most distant clusters of galaxies, new methods are needed.
Quasars are rare astronomical objects. If, as evidence suggests, their spatial distribution is similar to that of galaxies, then the presence of two or more quasars in the same small volume of space might indicate a region that is exceptionally rich in galaxies. A number of bona fide pairs and triplets of quasars are known to exist with small spatial and velocity separations. Because they can be seen to very high redshifts, such multiple quasar systems can serve as useful beacons for identifying galaxy clusters in the early universe.
My collaborators and I have found some evidence that quasar pairs are indeed excellent indicators of dense galaxy environments at z ~ 1. This suggests that the same technique could be useful for identifying quasars at even higher redshifts. But more work is needed. This project involves analyzing the cluster environments of quasar pairs and triplets at high redshifts using data obtained from several different telescopes.