9502220 Schaefer This award is made under the auspices of the NSF Faculty Early Career Development (CAREER) program. As a CAREER awardee the investigator is expected to pursue an active education plan in addition to his scientific research project. Gamma Ray Bursts are enigmatic flashes of gamma radiation which last typically from a second to a minute in duration. When they are bursting, their brightness varies chaotically, and they are by far the brightest source in the gamma ray sky. They are seen roughly once a day, from random directions, and at unpredictable times. Virtually no positive facts are known concerning the cause of gamma ray bursts, and this is traceable to the unfortunate circumstances that the distance scale to the bursters cannot be constrained to within 13 orders of magnitude. The population of bursts might be distributed among distant galaxies, in an extended halo around our Milky Way, or in our Sun's Oort Cloud. Until this distance scale question can be solved, gamma ray bursts must remain one of the biggest mysteries in modern astrophysics. Dr. Schaefer will attack the distance scale problem from several perspectives with the goal of finding a solution. In his education activities, Dr. Schaefer plans to integrate undergraduate and graduate students into the research projects through opportunities for undergraduate summer work, senior projects, graduate student summer work, and graduate thesis work. He will also continue public education activities with amateur astronomers to strengthen professional/amateur relationships.
