Center for Astrophysics Research and Technologies Seminar Series
The nature of faint polarized radio sources and their utility as cosmic probes
Presented by Chris Hales (NRAO)
A number of studies have reported an anti-correlation between fractional linear polarization and total intensity flux density for extragalactic 1.4 GHz sources; faint sources were found to be more highly polarized. As a result, the differential number-counts of polarized sub-millijansky sources have been observed to flatten to levels greater than expected from population modeling. This possibly indicates more ordered magnetic fields in faint sources or the emergence of an unexpected population. In this talk I will investigate the nature of faint polarized radio sources by presenting new results from a deep survey with the Australia Telescope Compact Array. I will describe tools developed to analyze the data, and present the resulting statistics of the faint polarized sky including number-counts and fractional polarization properties. To complement these results, I will summarize an emerging picture in the literature that updates the orientation-based interpretation of asymmetric depolarization in double radio sources and provides a direct link to probing AGN feedback. I will conclude by highlighting my plans to probe the unknown origin of cosmic magnetism using a dense grid of extragalactic polarized sources from a forthcoming ultra-deep survey with the Very Large Array.
2:00 pm, Thursday, March 27, 2014
PAIS-2540, PAIS
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