Bispectrum and Nonlinear Biasing of Galaxies: Perturbation Analysis, Numerical Simulation, and SDSS Galaxy Clustering

We consider nonlinear biasing models of galaxies with particular attention to a correlation between the linear and quadratic biasing coefficients, $b_1$ and $b_2$ . We first derive perturbative expressions for $b_1$ and $b_2$ in halo and peak biasing models. We then discuss our computations of the power spectra and bispectra of dark matter particles and halos using $N$ -body simulation data and of volume-limited subsamples of Sloan Digital Sky Survey (SDSS) galaxies, and determine their $b_1$ and $b_2$ . We find that the values of those coefficients at linear regimes ( $k