Date:   September 23, 2008 (Tuesday)
Time:   3:30 pm EDT (refreshments at 3:20 pm)
Place:  Green Bank Auditorium
         (Video: CV-230/AOC-AUD)

Speaker:  Rich Bradley, NRAO-Charlottesville

Title:  "The PAPER Trail: A Pathway to EoR Science"

Abstract:

Many secrets of the Universe have been revealed through the study of
hydrogen by radio, a technique pioneered by Doc Ewen and Ed Purcell
over 57 years ago when they pointed an antenna skyward in search of
neutral hydrogen's elusive radio signature.  Today, the frontiers of
modern cosmology take us back to the era of initial star formation -
the Epoch of Reionization (EoR).  A small group of researchers, in the
bricoleur spirit of Ewen and Purcell, have embarked on a scientific
adventure reminiscent of yesteryear in their attempt to find evidence
of HI as it appeared during Reionization.  Our instrument is the
Precision Array to Probe the Epoch of Reionization (PAPER).

PAPER is not a pathfinder in the conventional sense but the apparatus
of an experiment that is optimized for the detection of highly
red-shifted HI in the presence of strong foreground sources.  In
addition to the frontier science objective, the technical requirements
for PAPER are fostering new ideas and approaches for improving digital
signal processing, wide-field imagining, instrument stability,
calibration, dynamic range, and observing techniques;  ideas that will
also impact future instrumentation for radio astronomy.   We have
chosen an evolutionary approach to instrument development, a
philosophy by which we thoroughly analyze the performance and bound
the systematics of small prototype arrays before enhancing instrument
capabilities, as we methodically progress toward meeting our
scientific goals.  Compounding lessons learned along the way has
allowed us to confidently improve array performance and enhance
reliability in a cost-effective manner.

A snapshot of the PAPER project will be presented within the context
of scientific motivation, technical developments, current status, and
future plans.  The latest results will be presented.  In addition,
several spin-off activities (PAPER clips) will be described.

Future Colloquia:

http://www.gb.nrao.edu/colloquia/colloquia.html