Largescale galaxy bias
Abstract
This review presents a comprehensive overview of galaxy bias, that is, the statistical relation between the distribution of galaxies and matter. We focus on large scales where cosmic density fields are quasilinear. On these scales, the clustering of galaxies can be described by a perturbative bias expansion, and the complicated physics of galaxy formation is absorbed by a finite set of coefficients of the expansion, called bias parameters. The review begins with a detailed derivation of this very important result, which forms the basis of the rigorous perturbative description of galaxy clustering, under the assumptions of General Relativity and Gaussian, adiabatic initial conditions. Key components of the bias expansion are all leading local gravitational observables, which include the matter density but also tidal fields and their time derivatives. We hence expand the definition of local bias to encompass all these contributions. This derivation is followed by a presentation of the peakbackground split in its general form, which elucidates the physical meaning of the bias parameters, and a detailed description of the connection between bias parameters and galaxy statistics. We then review the excursionset formalism and peak theory which provide predictions for the values of the bias parameters. In the remainder of the review, we consider the generalizations of galaxy bias required in the presence of various types of cosmological physics that go beyond pressureless matter with adiabatic, Gaussian initial conditions: primordial nonGaussianity, massive neutrinos, baryonCDM isocurvature perturbations, dark energy, and modified gravity. Finally, we discuss how the description of galaxy bias in the galaxies' rest frame is related to clustering statistics measured from the observed angular positions and redshifts in actual galaxy catalogs.
 Publication:

Physics Reports
 Pub Date:
 February 2018
 DOI:
 10.1016/j.physrep.2017.12.002
 arXiv:
 arXiv:1611.09787
 Bibcode:
 2018PhR...733....1D
 Keywords:

 Cosmology;
 Dark matter;
 Galaxy bias;
 Galaxy clustering;
 Largescale structure;
 Primordial nonGaussianity;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Astrophysics  Astrophysics of Galaxies;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 259 pages, 39 figures, 15 tables