High time resolution observations of radio pulsars: The first detection of coherent emission.

摘要

Recent advances in recording technology and computational power have made possible the development of a wide bandwidth digital recording system for radio astronomy. A prototype 50 MHz bandwidth system along with two production systems with 10–50 MHz bandwidth have been designed and built at Caltech. Signal processing techniques have been developed in order to remove various artifacts introduced into the signal by the digitization process. These techniques along with various pulsar signal processing algorithms have been successfully implemented in a suite of highly portable analysis programs designed to run on multi-purpose parallel supercomputers, networked workstations, and stand-alone workstations. The single pulse radio emission properties of the bright millisecond pulsar PSR J0437-4715 have been studied using standard analysis methods. New techniques have been developed in order to study the single pulse properties of “weak” or low-intensity pulsars. These techniques have been used to analyze the pulse-to-pulse amplitude and pulse shape variations of the fastest millisecond pulsar PSR B1937+21. Techniques have also been developed in order to search for the presence of coherent non-Gaussian emission statistics. Such statistics have been detected in pulsars; B0823+26, B0950+08, and B1133+16. This is the first time such a phenomenon has been observed.