Description
As gravitational wave detectors become more sensitive, they will detect so many sources that individual events blend together to form a stochastic Gravitational Wave Background (GWB). Detecting anisotropies in this background could provide valuable insights into various cosmological and astrophysical properties. Given the strong expectation that LISA will detect the astrophysical GWB created by the extragalactic white dwarfs, we focus on the anisotropies of this specific background.
Anisotropies in the GWB have been extensively studied under the assumption that the universe is statistically isotropic and homogeneous. However, these assumptions break down on local scales due to the discrete distribution of galaxies. The properties of this discreteness are analyzed using simulations of isotropic universes. These simulations are also used to find a measure of anisotropy as a function of redshift. These findings are then used to analyze the inhomogeneity of the real stellar mass distribution using the Glade+ galaxy catalogue.
Our simulation results indicate that discreteness effects in the stellar mass distribution become negligible beyond 30 Mpc. Using both simulation data and Glade+, we find that 90% of the total anisotropy originates within 175 Mpc and more than 95% within 450 Mpc. Additionally, the GWB sky map constructed from Glade+ shows potential stochastic point sources from over-massive nearby galaxies. Moreover, incomplete electromagnetic data due to the Milky Way obscuration introduces uncertainties, which need to be addressed using proper masking techniques. Finally, we estimate that LISA can detect the multipoles $\ell=0$ and $\ell=2$, with $\ell=4$ potentially resolvable depending on observation time.
| Talk category | NOVA Network 3 |
|---|---|
| Preference for a talk or poster | Poster |
