Sensitivity Curves for GWB Anisotropy in PTAs

After more than 15 years of observations using pulsar timing arrays (PTAs), the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) and other PTA collaborations around the globe have found strong evidence for a stochastic gravitational wave background (GWB). The most probable source of this GWB is a population of inspiraling supermassive black hole binaries (SMBHBs). The yet to be uncovered anisotropy that is expected to arise from the non-uniform distribution of SMBHBs in the sky, as well as the individual parameters of those binaries, remains an interesting problem. Additionally, an anisotropic GWB can be an early harbinger of a continuous wave source from a single SMBHB rather than an isotropic cosmological source. Hasasia is a code developed to construct realistic sensitivity curves for PTAs such as those utilized in NANOGrav. This project aims to enhance Hasasia, specifically focusing on the new ability to account for the anticipated anisotropy in the GWB and its implication for future GWB searches.