The Association of American Universities on Wednesday announced that it had invited the Georgia Institute of Technology to become a member -- an offer the institute accepted immediately. Georgia Tech brings AAU membership to 63. The association is an invitation-only group whose members are selected on the basis of the breadth and quality of research and graduate programs, among other qualities. While universities do not formally apply to become members, many let it be known that they would like to be considered. Three quarters of existing members must approve any expansion. Georgia Tech is the first new member in nine years.