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A wide bandwidth pulsar timing machine

Posted on:1995-01-12Degree:Ph.DType:Thesis
University:California Institute of TechnologyCandidate:Navarro, JoseFull Text:PDF
GTID:2470390014990432Subject:Physics
Abstract/Summary:
Pulsar timing has turned millisecond pulsars into powerful tools for the study of neutron star physics, time-keeping, astrometry, the interstellar medium and binary systems. It uses millisecond pulsars as probes of the gravitational fields of their companions, of globular clusters and of the Galaxy, and provides information on the dynamics of the solar system. It has also confirmed predictions of general relativity, for which Joe Taylor and Russell Hulse received the 1993 Nobel Prize in Physics. Vasts amounts of information are expected as the current searches continue to discover new millisecond pulsars.; This thesis describes the design and construction of the Caltech Fast Pulsar Timing Machine and some preliminary results at the Parkes Observatory. The FPTM is a wide band timing machine built around a digital correlator for long-term timing stability and has a large observing bandwidth to time millisecond pulsars at high radio frequencies, where propagation effects are minimized.; It is the combination of the 128 MHz bandwidth, the 512 lag digital and the 1024 period phase bins with a minimum size 2.7 {dollar}mu{dollar}s that gives the FPTM its power. The large bandwidth makes new observations of faint pulsars possible above 1 GHz, where current receivers easily provide radio signals with more than 100 MHz of bandwidth. The large number of channels reduces the dispersion smearing of distant millisecond pulsars, which often defines the timing floor in timing systems, and the 1024 phase bins of 2.7 {dollar}mu{dollar}s or more ensure that the pulsar profile is adequately sampled.; We also present the discovery of J0218+4232, a very luminous binary field millisecond pulsar. Its 2.3 ms pulsations were only detected after an exhaustive search that involved building new hardware.
Keywords/Search Tags:Pulsar, Timing, Millisecond, Bandwidth
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