Anisotropies in the stochastic gravitational-wave background: Formalism and the cosmic string case

TL;DR

This paper introduces a comprehensive analytical framework for calculating the anisotropies in the stochastic gravitational-wave background, applicable to various sources, and demonstrates its application to cosmic strings, highlighting the impact of string tension.

Contribution

It provides a general formalism for anisotropy calculations in the gravitational-wave background and applies it specifically to cosmic strings, revealing key sensitivities.

Findings

Anisotropy spectrum is insensitive to string network models.

Anisotropy spectrum is highly sensitive to string tension Gμ.

Framework can be applied to diverse astrophysical sources.

Abstract

We develop a powerful analytical formalism for calculating the energy density of the stochastic gravitational wave background, including a full description of its anisotropies. This is completely general, and can be applied to any astrophysical or cosmological source. As an example, we apply these tools to the case of a network of Nambu-Goto cosmic strings. We find that the angular spectrum of the anisotropies is relatively insensitive to the choice of model for the string network, but very sensitive to the value of the string tension $G\mu$.