Measuring Coherent Motions in the Universe

Abstract

We present new measurements of the coherent motion of galaxies based on observations of the large-scale redshift-space distortions seen in the two-dimensional two-point correlation function of Luminous Red Galaxies in Data Release Seven of the Sloan Digital Sky Survey. We have developed a new methodology for estimating these coherent motions, which is less dependent on the details of galaxy bias and of the cosmological model to explain the late-time acceleration of the expansion of the Universe. We measure a one-dimensional velocity dispersion of galaxies on large-scales of σ_v=3.01^{+0.45}_{-0.46} Mpc/h and σ_v=3.69^{+0.47}_{-0.47} \mpcoh$atameanredshiftofz=0.25and0.38respectively.ThesevaluesarefullyconsistentwithpredictionsforaWMAP7-normalisedLCDMUniverseandinconsistentatconfidenceof3.8\sigma withaDvali-Gabadadze-Porrati(DGP)modelfortheUniverse.Wecanconverttheunitsofthese$σ_v$measurementsto270_{-41}^{+40}km/sand320_{-41}^{+41}km/srespectively(assuminga$Λ$CDM universe), which are lower that expected based on recent low redshift (z<0.2) measurements of the peculiar velocity field (or "bulk flows"). It is difficult to directly compare these measurements as they cover different redshift ranges and different areas of the sky. However, one possible cosmological explanation for this discrepancy is that our Galaxy is located in unusually over, or under, dense region of the Universe.

11 pages, 7 figures

References in corpus (15)

• A test of the nature of cosmic acceleration using galaxy redshift distortions
• Baryon Acoustic Oscillations in 2D: Modeling Redshift-space Power Spectrum from Perturbation Theory
• The clustering of massive galaxies at z~0.5 from the first semester of BOSS data
• Observational Tests of Modified Gravity
• The 2dF-SDSS LRG and QSO Survey: The LRG 2-Point Correlation Function and Redshift-Space Distortions
• Clustering of luminous red galaxies I: large scale redshift space distortions
• Modelling redshift space distortions in hierarchical cosmologies
• The Three-Point Correlation Function of Luminous Red Galaxies in the Sloan Digital Sky Survey
• Consistency test of general relativity from large scale structure of the Universe
• Systematic Effects on Determination of the Growth Factor from Redshift-space Distortions
• Effects of cosmological model assumptions on galaxy redshift survey measurements
• Current Status Of Velocity Field Surveys: A Consistency Check
• A step towards testing general relativity using weak gravitational lensing and redshift surveys
• Enabling Rapid Development of Parallel Tree Search Applications
• An Improved Photometric Calibration of the Sloan Digital Sky Survey Imaging Data

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• Cosmological Constraints from the Anisotropic Clustering Analysis using BOSS DR9
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