A robust constraint on cosmic textures from the cosmic microwave
  background
  Fluctuations in the cosmic microwave background (CMB) contain information
which has been pivotal in establishing the current cosmological model. These
data can also be used to test well-motivated additions to this model, such as
cosmic textures. Textures are a type of topological defect that can be produced
during a cosmological phase transition in the early universe, and which leave
characteristic hot and cold spots in the CMB. We apply Bayesian methods to
carry out a rigorous test of the texture hypothesis, using full-sky data from
the Wilkinson Microwave Anisotropy Probe. We conclude that current data do not
warrant augmenting the standard cosmological model with textures. We rule out
at 95% confidence models that predict more than 6 detectable cosmic textures on
the full sky.
