Characterizing the Performance of the Precision Array for Probing the Epoch of Reionization 1125 views

With better telescopes and observing techniques, astronomers have entered the age of precision observational cosmology. The processes of formation of the first stars and galaxies is still a mystery to us, however, as our optical and infrared telescopes are not yet powerful enough to see back to these events that occurred over 12 billion years ago in what has been coined the epoch of reionization, or EoR. The search for this signal has pushed radio astronomy to lower frequencies than have traditionally been used. This low-frequency regime is complicated by strong foreground sources, such as the emission of our own galaxy, human-made radio frequency interference, and the Earth's refractive and turbulent ionosphere. PAPER (The Precision Array for Probing the Epoch of Reionization) is a collaboration between the University of Virginia, the National Radio Astronomy Observatory, University of California at Berkeley, University of Pennsylvania, and the Square Kilometer Array consortium in South Africa. PAPER will consist of a 128-antenna array of sleeved dipoles with a clean reception pattern over the entire frequency range of interest. This thesis reports on work mainly done with the PAPER array in Green Bank at various stages of development. I will describe the planning of the array and various steps in the deployment and calibration process. In the early days of the experiment, it was ideal to determine the receiver temperature of the instrument in the field. This led to the discovery of a stability issue with amplifiers in the PAPER system which were then characterized to achieve the desired imaging capability. As PAPER became more sensitive and could begin to image fainter sources on the sky,theionospherebecamemoreofaconcernforpresentandfutureobservations. The brightest sources were tracked over short timescales. After calibrating for antenna v positions, the brightest sources in the sky were shown to be changing position on the scale of arcminutes over short timescales. The implications of these findings in light of near and long-term EoR observations and other astronomical projects are discussed. Note: Abstract extracted from PDF text

PHD (Doctor of Philosophy)

English

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2012-08-01