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Theoretical modeling of the redshift-space power spectrum of galaxies iscrucially important to correctly extract cosmological information from redshiftsurveys. The task is complicated by the nonlinear biasing and redshift spacedistortion effects, which change with halo mass, and by the wide distributionof halo masses and their occupations by galaxies. One of the main modelingchallenges is the existence of satellite galaxies that have both radialdistribution and large virial velocities inside halos, a phenomenon known asthe Finger-of-God effect. We present a model for the galaxy power spectrum ofin which we decompose a given galaxy sample into central and satellite galaxiesand relate different contributions to 1- and 2-halo terms in a halo model. Ourprimary goal is to ensure that any parameters that we introduce have physicallymeaningful values, and are not just fitting parameters. For the 2-halo terms weuse the previously developed RSD modeling of halos in the context ofdistribution function and perturbation theory approach. This term needs to bemultiplied by the effect of radial distances and velocities of satellitesinside the halo. To this one needs to add the 1-halo terms, which arenon-perturbative. We show that the real space 1-halo terms can be modeled asalmost constant, with the finite extent of the satellites inside the haloinducing a small k^2R^2 term, where R is related to the size of the halo. Weadopt a similar model for FoG in redshift space, ensuring that FoG velocitydispersion is related to the halo mass. For FoG k^2 type expansions do not workand FoG resummation must be used instead. We test several damping functions tomodel the velocity dispersion FoG effect. Applying the formalism to mockgalaxies modeled after the "CMASS" sample of the BOSS survey, we find that ourpredictions for the redshift-space power spectra are accurate up to k~0.4Mpc/h.

Galaxy power spectrum in redshift space: combining perturbation theory with the halo model