Multi-Tracer Correlated Stacking for Anisotropy in the nano-Hz Gravitational-Wave Background
A statistical technique for detecting anisotropy in the nano-hertz stochastic gravitational-wave background sourced by supermassive black-hole binaries. Because that background is non-Gaussian and anisotropic (hosted by relatively few massive galaxies), angular power spectra are insufficient; Multi-Tracer Correlated Stacking instead stacks the GW signal over sky regions tagged by black-hole tracers (AGN, quasars, bright galaxies) that map the matter distribution to high redshift, cleanly separating isotropic from anisotropic source distributions and outperforming angular-power-spectrum methods.
Draft version March 18, 2025 Typeset using LATEX default style in AASTeX631 Multi-Tracer Correlated
The nano-hertz stochastic gravitational-wave background (SGWB), recently evidenced by pulsar timing arrays, is expected to be sourced by inspiraling supermassive black-hole binaries (SMBHBs). Because…