Peak-peak correlations in the cosmic background radiation from cosmic strings

Abstract

We examine the two-point correlation function of local maxima in temperature fluctuations at the last scattering surface when this stochastic field is modified by the additional fluctuations produced by straight cosmic strings via the Kaiser-Stebbins effect. We demonstrate that one can detect the imprint of cosmic strings with tension Gμ > 1.2 × 10-8 on noiseless 1 arcmin resolution cosmic microwave background (CMB) maps at 95 per cent confidence interval. Including the effects of foregrounds and anticipated systematic errors increases the lower bound to Gμ > 9.0 × 10-8 at 2s confidencelevel. Smearing by beams of the order of 4 arcmin degrades the bound further to Gμ > 1.6 × 10-7. Our results indicate that two-point statistics are more powerful than one-point statistics (e.g. number counts) for identifyingthe non-Gaussianity in the CMB due to straight cosmic strings. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.