Using galaxy pairs as cosmological tracers

Abstract

The Alcock-Paczynski (AP) effect uses the fact that, when analyzed with the correct geometry, we should observe structure that is statistically isotropic in the Universe. For structure undergoing cosmological expansion with the background, this constrains the product of the Hubble parameter and the angular diameter distance. However, the expansion of the Universe is inhomogeneous and local curvature depends on density. We argue that this distorts the AP effect on small scales. After analyzing the dynamics of galaxy pairs in the Millennium simulation, we find an interplay between peculiar velocities, galaxy properties and local density that affects how pairs trace cosmological expansion. We find that only low mass, isolated galaxy pairs trace the average expansion with a minimum "correction" for peculiar velocities. Other pairs require larger, more cosmology and redshift dependent peculiar velocity corrections and, in the small-separation limit of being bound in a collapsed system, do not carry cosmological information.

15 pages, 14 figures, 1 table

References in corpus (17)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• Populating a cluster of galaxies - I. Results at z=0
• The broken hierarchy of galaxy formation
• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• From dwarf spheroidals to cDs: Simulating the galaxy population in a LCDM cosmology
• Science Objectives and Early Results of the DEEP2 Redshift Survey
• Measuring the cosmological constant with redshift surveys
• The Colours of Satellite Galaxies in Groups and Clusters
• Towards an accurate model of the redshift space clustering of halos in the quasilinear regime
• On The Validity of the Streaming Model for the Redshift-Space Correlation Function in the Linear Regime
• Effects of cosmological model assumptions on galaxy redshift survey measurements
• The DEEP2 Galaxy Redshift Survey: Probing the Evolution of Dark Matter Halos around Isolated Galaxies at z ~ 1
• Testing dark energy using pairs of galaxies in redshift space
• Locating the Baryon Acoustic Peak

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• A first application of the Alcock-Paczynski test to stacked cosmic voids
• The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
• Cosmological constraints from the redshift dependence of the Alcock-Paczynski effect: Dynamical dark energy
• Cosmological constraints from the redshift dependence of the Alcock-Paczynski test and volume effect: galaxy two-point correlation function
• Cosmological constraints from the redshift dependence of the volume effect using the galaxy 2-point correlation function across the line-of-sight
• Isolating the linear signal when making redshift space distortion measurements