The history and large-scale properties of the Universe are now well understood, mostly because of detailed observations of the fluctuations in the temperature of the cosmic microwave background (CMB). The crucial next step in observational cosmology is the detection and characterization of polarized fluctuations in the CMB, which are unfortunately much smaller in amplitude. The present research program has two major components: to examine the polarization of inverted spectrum and gigahertz-peaked radio sources using the Very Large Array and the Very Long Baseline Array, and to investigate the possibility that a previously undetected spectral line of neutral hydrogen (at 10GHz) might be used to investigate the epoch of reionization. The first of these will help to determine if radio sources that become prominent at high frequencies could constitute a major contaminant for future CMB polarization studies. The second is a speculative but potentially important new avenue for investigation of the early Universe.
The major broader impact of this research lies in the encouragement and training of undergraduate students at a predominantly undergraduate school. Haverford College, and this researcher in particular, has a fine record of sending students on to careers in astronomy and related fields, and these projects will help maintain that record. Also included in the program are pedagogical research, writing and talks on the history of the CMB, and efforts to bring radio astronomy research to students in developing nations.
