Cosmic strings in the age of Boomerang

Abstract

We show how two simple modifications to the standard cosmic string scenario for structure formation compare to the recently released Boomerang data set. Namely we consider pure string closed models and mixed models where both inflation and strings are responsible for the perturbations. In the closed models we find that pure string models would require a universe with roughly $Ω_M=0.8$, $Ω_Λ=1.6$ to agree with the peak position revealed by the data and in agreement with the SNIa data. In the hybrid scenario with local strings we find that we require even more tilt and baryon content ($n_s\sim 0.8$, $Ω_b=0.08$, $H_0=70$) to match the data than with pure inflation models. The case with global strings fares better with a standard period of $Λ$CDM inflation and a $\sim30%$ contribution from strings being in good agreement with the data.