Volume 583, November 2015
|Number of page(s)||7|
|Section||Cosmology (including clusters of galaxies)|
|Published online||27 October 2015|
Constraining cosmology with pairwise velocity estimator
Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The
University of Manchester,
2 Astrophysics and Cosmology Research Unit, School of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4001, South Africa
3 Changchun Observatory, National Astronomical Observatories, CAS, Changchun, Jilin 130117, PR China
4 College of Physics, Jilin University, Changchun 130012, PR China
5 Center for High Energy Physics, Peking University, Beijing 100871, PR China
Received: 8 March 2015
Accepted: 3 August 2015
In this paper, we develop a full statistical method for the pairwise velocity estimator previously proposed, and apply Cosmicflows-2 catalogue to this method to constrain cosmology. We first calculate the covariance matrix for line-of-sight velocities for a given catalogue, and then simulate the mock full-sky surveys from it, and then calculate the variance for the pairwise velocity field. By applying the 8315 independent galaxy samples and compressed 5224 group samples from Cosmicflows-2 catalogue to this statistical method, we find that the joint constraint on Ωm0.6h and σ8 is completely consistent with the WMAP 9-year and Planck 2015 best-fitting cosmology. Currently, there is no evidence for the modified gravity models or any dynamic dark energy models from this practice, and the error-bars need to be reduced in order to provide any concrete evidence against/to support ΛCDM cosmology.
Key words: large-scale structure of Universe / distance scale / cosmology: observations / galaxies: kinematics and dynamics / methods: statistical / methods: data analysis
© ESO, 2015
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