Exploring the Anisotropic Gravitational Wave Background from All-sky Mock Gravitational Wave Event Catalogs
Anisotropic stochastic gravitational wave background (SGWB) serves as a potential probe of the large-scale structure (LSS) of the universe. In this work, we explore the anisotropic SGWB from local ( z < ∼ 0.085) merging stellar mass compact binaries, specifically focusing on merging stellar binar...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/adca36 |
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| Summary: | Anisotropic stochastic gravitational wave background (SGWB) serves as a potential probe of the large-scale structure (LSS) of the universe. In this work, we explore the anisotropic SGWB from local ( z < ∼ 0.085) merging stellar mass compact binaries, specifically focusing on merging stellar binary black holes, merging neutron star–black hole binaries, and merging binary neutron stars. The analysis employs seven all-sky mock lightcone gravitational wave event catalogs, which are derived from the Millennium simulation combined with a semianalytic model of galaxy formation and a binary population synthesis model. We calculate the angular power spectra C _ℓ at multipole moments ℓ , expressed as log _10 [ ℓ ( ℓ + 1)C _ℓ /(2 π )], based on the skymaps of the overdensity δ _GW in the anisotropic SGWB. The spectra for all three source types exhibit an approximately linear increase with log _10 ℓ at higher ℓ (e.g., ℓ > ∼ 30–300) in seven catalogs, with a characteristic slope of ∼2. The spectra of seven catalogs exhibit considerable variations, arising from fluctuations in spatial distribution, primarily in the radial distribution, of nearby sources (e.g., <50 Mpc h ^−1 ). After subtracting these nearby sources, the variations become much smaller and the spectra for the three source types become closely aligned (within discrepancies of a factor of ∼2 across ℓ = 1–1000 for all catalogs). We also find that including farther sources results in a rapid decrease in the anisotropy. |
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| ISSN: | 1538-4357 |