Fundamental limits of radio interferometers: calibration and source
  parameter estimation
  We use information theory to derive fundamental limits on the capacity to
calibrate next-generation radio interferometers, and measure parameters of
point sources for instrument calibration, point source subtraction, and data
deconvolution. We demonstrate the implications of these fundamental limits,
with particular reference to estimation of the 21cm Epoch of Reionization power
spectrum with next-generation low-frequency instruments (e.g., the Murchison
Widefield Array -- MWA, Precision Array for Probing the Epoch of Reionization
-- PAPER), where short time scale instrumental calibration is required due to
the impact of the ionosphere on the signal wavefront. Finally, we explore the
optimal point source precision available by using a combination of current and
prior information. Estimation schemes that incorporate prior information may be
advantageous when the measurement precision is comparable to the characteristic
refraction scale of the ionosphere.
