Scientific Justification for a Beam-Forming Array on the Green Bank Telescope

摘要

National Radio Astronomy Observatory (NRAO) plans to build a beam- forming array for the Green Bank Telescope (GBT) capable of producing seven beams at L-band. The physical size of 21-cm feeds at the GBT makes it impossible to support a system with more than three beams if they are formed in the traditional fashion by stacking feed horns side by side. The beam-forming array is the most natural, efficient, and logical way to gain the advantage, and would represent a breakthrough in technology. Such an instrument would open up many new survey possibilities in spectral line and continuum imaging and polarization, as well as searches for new pulsars along the Galactic Plane. This document presents justifications and sample observing parameters for these surveys along with required system specification.