Searching for Signatures of Cosmic String Wakes in 21cm Redshift Surveys
  using Minkowski Functionals
  Minkowski Functionals are a powerful tool for analyzing large scale
structure, in particular if the distribution of matter is highly non-Gaussian,
as it is in models in which cosmic strings contribute to structure formation.
Here we apply Minkowski functionals to 21cm maps which arise if structure is
seeded by a scaling distribution of cosmic strings embeddded in background
fluctuations, and then test for the statistical significance of the cosmic
string signals using the Fisher combined probability test. We find that this
method allows for detection of cosmic strings with $G \mu > 5 \times 10^{-8}$,
which would be improvement over current limits by a factor of about 3.
