期刊
ASTROPHYSICAL JOURNAL
卷 758, 期 2, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/758/2/130
关键词
cosmic background radiation; cosmology: observations; galaxies: peculiar; large-scale structure of universe
资金
- National Science Foundation of China (NSFC) [11073024]
- John Templeton Foundation
- NSFC [10821302, 10973027, 11025316]
- CAS/SAFEA [KJCX2-YW-T23]
- National Basic Research Program of China (973 Program) [2009CB24901]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy
- National Aeronautics and Space Administration
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- American Museum of Natural History
- Astrophysical Institute Potsdam
- University of Basel
- Cambridge University
- Case Western Reserve University
- University of Chicago
- Drexel University
- Institute for Advanced Study
- Japan Participation Group
- Johns Hopkins University
- Joint Institute for Nuclear Astrophysics
- Kavli Institute for Particle Astrophysics and Cosmology
- Korean Scientist Group
- Chinese Academy of Sciences (LAMOST)
- Los Alamos National Laboratory
- Max-Planck-Institute for Astronomy (MPIA)
- Max-Planck-Institute for Astrophysics (MPA)
- New Mexico State University
- Ohio State University
- University of Pittsburgh
- University of Portsmouth
- Princeton University
- United States Naval Observatory
- University of Washington
- Fermilab
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(DF)) angular dependence, and hence can be distinguished from other components. Here,theta(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(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 (greater than or similar to 6000 km s(-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.
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