Informal Pizza Seminar

Cosmic Strings and Small-Angle CMB Temperature Anisotropies

Aurelian Fraisse

Princeton University

After briefly introducing cosmic strings as astronomical objects, I will review constraints on their existence, and on models generically predicting them, from current CMB data. Although full-sky observations of the CMB, in particular WMAP's, provide interesting results at large angular scales, cosmic strings have long been expected to have a much greater effect at small scales. I will present simulations of the evolution of a network of Nambu-Goto cosmic strings from the surface of last scattering to the present day in the small-angle limit. The inferred CMB temperature maps exhibit highly non-Gaussian features that could potentially be detected by arcminute-resolution CMB experiments such as the Atacama Cosmology Telescope (ACT), the South Pole Telescope (SPT), or the Arcminute Microkelvin Imager (AMI). I will show the results of a preliminary analysis giving an idea of the extent to which strings could be detected by an ACT-like experiment, taking into account beam and other secondary effects.