Member Directory The AAS maintains a membership directory to facilitate member interaction and to support the conduct of official Society business. Search directory for: Filter Results By Clear Filters Type of Science Active Galactic Nu (4) Galaxy Formation & Evolu (3) GRBs (3) High-Energy Pheno (3) Supernovae (3) Clusters of Galaxies/Large-scale Struc (1) Interstellar Me (1) (-) Astronomy Educa (1) State NY (1) Facet State City Acton (1) Alexandria (1) Ames (1) Austin (1) Baltimore (1) Berkeley (2) Bothell (2) Cambridge (5) Chicago (1) College Station (1) Daejeon (1) Fort Myers (1) Iowa City (1) Madison (1) Middlebury (1) Middletown (1) Newark (1) New London (1) Pasadena (3) Prescott (1) Santa Fe (1) Severna Park (1) Stanford (1) Tempe (1) Washington (1) Winnipeg (1) (-) New York (1) Facet City Membership Class (-) Full Member (1) Facet Membership Class Division (-) HEAD (1) Facet Division Showing 1-1 of 1 results David Helfand Full Member Affiliation Columbia University State/Province NY Country United States