  We study the cross-correlation between the stochastic gravitational-wave
background (SGWB) generated by binary black hole (BBH) mergers across the
universe and the distribution of galaxies across the sky. We use the
anisotropic SGWB measurement obtained using data from the third observing run
(O3) of Advanced LIGO detectors and galaxy over-density obtained from the Sloan
Digital Sky Survey (SDSS) spectroscopic catalog. We compute, for the first
time, the angular power spectrum of their cross-correlation. Instead of
integrating the SGWB across frequencies, we analyze the cross-correlation in 10
Hz wide SGWB frequency bands to study the frequency dependence of the
cross-correlation angular power spectrum. Finally, we compare the observed
cross-correlation to the spectra predicted by astrophysical models. We apply a
Bayesian formalism to explore the parameter space of the theoretical models,
and we set constraints on a set of (effective) astrophysical parameters
describing the galactic process of gravitational wave (GW) emission.
Parameterizing with a Gaussian function the astrophysical kernel describing the
local process of GW emission at galactic scales, we find the 95\% upper limit
on kernel amplitude to be $2.7 \times 10^{-32}$ erg cm$^{-3}$s$^{-1/3}$ when
ignoring the shot noise in the GW emission process, and $2.16 \times 10^{-32}$
erg cm$^{-3}$s$^{-1/3}$ when the shot noise is included in the analysis. As the
sensitivity of the LIGO-Virgo-KAGRA network improves, we expect to be able to
set more stringent bounds on this kernel function and constrain its parameters.
