Effects of Cosmic Strings on Free Streaming

Abstract

We study the effect of free streaming in a universe with cosmic strings with time-varying tension as well as with constant tension. Although current cosmological observations suggest that fluctuation seeded by cosmic strings cannot be the primary source of cosmic density fluctuation, some contributions from them are still allowed. Since cosmic strings actively produce isocurvature fluctuation, the damping of small scale structure via free streaming by dark matter particles with large velocity dispersion at the epoch of radiation-matter equality is less efficient than that in models with conventional adiabatic fluctuation. We discuss its implications to the constraints on the properties of particles such as massive neutrinos and warm dark matter.

arXiv comment14 pages, 9 figures

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Cited by in corpus (3)

• Constraints on primordial isocurvature perturbations and spatial curvature by Bayesian model selection
• Constraints on scalar and tensor perturbations in phenomenological and two-field inflation models: Bayesian evidences for primordial isocurvature and tensor modes
• Adiabatic fluctuations from cosmic strings in a contracting universe