We study the distribution of dark matter in the nonlinear regime in a model in which the primordial fluctuations include, in addition to the dominant primordial Gaussian fluctuations generated by the standard $\mathrm{\Lambda }\mathrm{CDM}$ cosmological model, the effects of a cosmic string wake set up at the time of equal matter and radiation, making use of cosmological $N$-body simulations. At early times, the string wake leads to a planar overdensity of dark matter. We study how this non-Gaussian pattern of a cosmic string wake evolves in the presence of the Gaussian perturbations, making use of wavelet and ridgeletlike statistics specifically designed to extract string wake signals. At late times, the Gaussian fluctuations disrupt the string wake. We find that for a string tension of $G\mu ={10}^{-7}$, a value just below the current observational limit, the effects of a string wake can be identified in the dark matter distribution, using the current level of the statistical analysis, down to a redshift of $z=10$.

• Received 12 April 2018

DOI:https://doi.org/10.1103/PhysRevD.98.083015