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“A New Era of Gamma-ray Pulsars”
Sarah A. Story and
Department of Physics, Hope College
Friday, March 2, 2007 104 VWF at 3:00 p.m.
Since their initial discovery in 1967, more than 1600 pulsars, including about 150 ultra-fast millisecond pulsars, have been discovered, mostly by ground-based radio telescopes. The launch of the Compton Gamma-ray Observatory (CGRO) in 1991 made it possible to detect gamma-ray emission from six gamma-ray pulsars with high confidence and a few others with lower confidence, including a binary millisecond pulsar with a rotational period of 2.3 ms and an orbital period of 2.03 days. EGRET, the instrument aboard CGRO that was sensitive to pulsars, could only detect pulses from the brightest gamma-ray pulsars. Now, new instruments promise to revolutionize our understanding of high-energy emission from pulsars by dramatically increasing the number of known gamma-ray pulsars. AGILE, an Italian satellite, will be launched at the end of the month, and GLAST, a collaboration between NASA and European space agencies, is scheduled for launch in the fall. We attempt to understand the geometry and luminosity of radio and gamma-ray emission from pulsars by simulating the characteristics of these beams and predicting their detectability by radio surveys as well as by the gamma-ray instruments EGRET, AGILE and GLAST. By exploring the correlations of the radio and gamma-ray beams, we try to pinpoint the location within the magnetosphere of the region producing the gamma-ray emission. We present some results of our population statistics synthesis of radio and gamma-ray pulsars, which include both normal and millisecond pulsars, and make predictions for AGILE and GLAST.