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 (2) GRBs (2) High-Energy Pheno (2) Supernovae (2) Galaxy Formation & Evolu (1) Interstellar Me (1) (-) Astronomy Educa (1) State (-) NY (1) Facet State City Berkeley (1) (-) New York (1) Facet City Membership Class (-) Full Member (1) Facet Membership Class Division DDA (1) (-) HEAD (1) Facet Division Showing 1-1 of 1 results David Helfand Full Member Affiliation Columbia University State/Province NY Country United States