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A robust constraint on cosmic textures from the cosmic microwave background

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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 an optimal 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.