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Title: ANOMALOUS ANISOTROPIC CROSS-CORRELATIONS BETWEEN WMAP CMB MAPS AND SDSS GALAXY DISTRIBUTION AND IMPLICATIONS ON THE DARK FLOW SCENARIO

Abstract

We search for the dark flow induced diffuse kinetic Sunyaev-Zel'dovich (kSZ) effect through CMB-galaxy cross-correlation. Such angular correlation is anisotropic, with a unique cos ({theta}{sub DF}) angular dependence, and hence can be distinguished from other components. Here, {theta}{sub DF} is the angle between the opposite dark flow direction and the direction of the sky where the correlation is measured. We analyze the KIAS-VAGC galaxy catalog of SDSS-DR7 and the WMAP seven-year temperature maps, applying an unbiased optimal weighting scheme to eliminate any statistically isotropic components and to enhance the dark flow detection signal. Non-zero weighted cross-correlations are detected at 3.5 {sigma} for the redshift bin z < 0.1 and at 3 {sigma} for the bin 0.1 < z < 0.2, implying the existence of statistically anisotropic components in CMB. However, further analysis does not support the dark flow explanation. The observed directional dependence deviates from the {proportional_to}cos {theta}{sub DF} relation expected, and hence cannot be explained by the presence of a single dark flow, and if the observed cross-correlation is generated by the dark flow induced kSZ effect, the velocity would be too high ({approx}> 6000 km s{sup -1}). We report this work as the first attempt to search formore » dark flow through weighted CMB-galaxy cross-correlation and to draw the attention on the sources of the detected anomalous CMB-galaxy cross-correlation.« less

Authors:
;  [1];  [2]
  1. Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Science, Beijing 100012 (China)
  2. Key Laboratory for Research in Galaxies and Cosmology, Shang Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China)
Publication Date:
OSTI Identifier:
22086510
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 758; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR CORRELATION; ANISOTROPY; ASTRONOMY; ASTROPHYSICS; CATALOGS; COSMOLOGY; GALAXIES; MAPPING; RADIATION DETECTION; RED SHIFT; RELICT RADIATION; SPATIAL DISTRIBUTION; UNIVERSE; VELOCITY

Citation Formats

Li Zhigang, Chen Xuelei, and Zhang Pengjie, E-mail: zgli@bao.ac.cn, E-mail: pjzhang@shao.ac.cn, E-mail: xuelei@cosmology.bao.ac.cn. ANOMALOUS ANISOTROPIC CROSS-CORRELATIONS BETWEEN WMAP CMB MAPS AND SDSS GALAXY DISTRIBUTION AND IMPLICATIONS ON THE DARK FLOW SCENARIO. United States: N. p., 2012. Web. doi:10.1088/0004-637X/758/2/130.
Li Zhigang, Chen Xuelei, & Zhang Pengjie, E-mail: zgli@bao.ac.cn, E-mail: pjzhang@shao.ac.cn, E-mail: xuelei@cosmology.bao.ac.cn. ANOMALOUS ANISOTROPIC CROSS-CORRELATIONS BETWEEN WMAP CMB MAPS AND SDSS GALAXY DISTRIBUTION AND IMPLICATIONS ON THE DARK FLOW SCENARIO. United States. doi:10.1088/0004-637X/758/2/130.
Li Zhigang, Chen Xuelei, and Zhang Pengjie, E-mail: zgli@bao.ac.cn, E-mail: pjzhang@shao.ac.cn, E-mail: xuelei@cosmology.bao.ac.cn. Sat . "ANOMALOUS ANISOTROPIC CROSS-CORRELATIONS BETWEEN WMAP CMB MAPS AND SDSS GALAXY DISTRIBUTION AND IMPLICATIONS ON THE DARK FLOW SCENARIO". United States. doi:10.1088/0004-637X/758/2/130.
@article{osti_22086510,
title = {ANOMALOUS ANISOTROPIC CROSS-CORRELATIONS BETWEEN WMAP CMB MAPS AND SDSS GALAXY DISTRIBUTION AND IMPLICATIONS ON THE DARK FLOW SCENARIO},
author = {Li Zhigang and Chen Xuelei and Zhang Pengjie, E-mail: zgli@bao.ac.cn, E-mail: pjzhang@shao.ac.cn, E-mail: xuelei@cosmology.bao.ac.cn},
abstractNote = {We search for the dark flow induced diffuse kinetic Sunyaev-Zel'dovich (kSZ) effect through CMB-galaxy cross-correlation. Such angular correlation is anisotropic, with a unique cos ({theta}{sub DF}) angular dependence, and hence can be distinguished from other components. Here, {theta}{sub DF} is the angle between the opposite dark flow direction and the direction of the sky where the correlation is measured. We analyze the KIAS-VAGC galaxy catalog of SDSS-DR7 and the WMAP seven-year temperature maps, applying an unbiased optimal weighting scheme to eliminate any statistically isotropic components and to enhance the dark flow detection signal. Non-zero weighted cross-correlations are detected at 3.5 {sigma} for the redshift bin z < 0.1 and at 3 {sigma} for the bin 0.1 < z < 0.2, implying the existence of statistically anisotropic components in CMB. However, further analysis does not support the dark flow explanation. The observed directional dependence deviates from the {proportional_to}cos {theta}{sub DF} relation expected, and hence cannot be explained by the presence of a single dark flow, and if the observed cross-correlation is generated by the dark flow induced kSZ effect, the velocity would be too high ({approx}> 6000 km s{sup -1}). We report this work as the first attempt to search for dark flow through weighted CMB-galaxy cross-correlation and to draw the attention on the sources of the detected anomalous CMB-galaxy cross-correlation.},
doi = {10.1088/0004-637X/758/2/130},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 758,
place = {United States},
year = {2012},
month = {10}
}