Dr. Weisberg will carry out a research program on pulsars in three areas: (i) Studies of relativistic gravitation with the binary pulsar PSR 1913+16. The data will be used to study gravitational wave emission from the binary orbiting system, the cosmic background of ultra-long period gravitational radiation, time variation of the Newtonian gravitational constant, and geodetic spin precession. (ii) Measurements of pulsar distances and the interstellar medium. The data should yield pulsar distances, interstellar electron densities, and details of the small-scale structure of cool neutral atomic hydrogen. (iii) A pulsar timing and polarimetry survey. Approximately one hundred pulsars will be monitored quarterly to measure pulse arrival times and polarization properties of the emission. These data will be used to study pulse emission mechanisms, glitches, timing noise, slow scintillations, and free precession. Pulsars observed at radio wavelengths are among the best probes of relativistic gravitation and the diffuse interstellar medium. Analysis of pulsar signals has led to the first experimental proof of the existence of gravitational radiation, limits on the energy density of a cosmic background of gravitational radiation, and measurements of the electron density and magnetic field of the interstellar medium. Dr. Weisberg will continue his highly regarded investigations of relativistic gravitation and the interstellar medium, in addition to studying the intrinsic properties of radio wavelength emissions from pulsars. This award is made under the auspices of the Research in Undergraduate Institutions (RUI) program at the National Science Foundation.
