Bilicki, Maciej and Chodorowski, Michał and Jarrett, Thomas and Mamon, Gary A. (2011) Is the Two Micron all Sky Survey Clustering Dipole Convergent? Astrophysical Journal, 741 (1). Art. No. 31. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20111206-071137974
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There is a long-standing controversy about the convergence of the dipole moment of the galaxy angular distribution (the so-called clustering dipole). Is the dipole convergent at all, and if so, what is the scale of the convergence? We study the growth of the clustering dipole of galaxies as a function of the limiting flux of the sample from the Two Micron All Sky Survey (2MASS). Contrary to some earlier claims, we find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e., up to 13.5 mag in the near-infrared K_s band (equivalent to an effective distance of 300 Mpc h ^(−1)). We compare the observed growth of the dipole with the theoretically expected, conditional one (i.e., given the velocity of the Local Group relative to the cosmic microwave background), for the ΛCDM power spectrum and cosmological parameters constrained by the Wilkinson Microwave Anisotropy Probe. The observed growth turns out to be within 1σ confidence level of its theoretical counterpart once the proper observational window of the 2MASS flux-limited catalog is included. For a contrast, if the adopted window is a top hat, then the predicted dipole grows significantly faster and converges (within the errors) to its final value for a distance of about 300 Mpc h ^(−1). By comparing the observational windows, we show that for a given flux limit and a corresponding distance limit, the 2MASS flux-weighted window passes less large-scale signal than the top-hat one. We conclude that the growth of the 2MASS dipole for effective distances greater than 200 Mpc h^(−1) is only apparent. On the other hand, for a distance of 80 Mpc h^(−1) (mean depth of the 2MASS Redshift Survey) and the ΛCDM power spectrum, the true dipole is expected to reach only ~80% of its final value. Eventually, since for the window function of 2MASS the predicted growth is consistent with the observed one, we can compare the two to evaluate β ≡ Ω^(0.55)_m /b. The result is β = 0.38 ± 0.04, which leads to an estimate of the density parameter Ω_m = 0.20 ± 0.08.
|Additional Information:||© 2011 The American Astronomical Society. Received 2011 May 16; accepted 2011 August 1; published 2011 October 12. The authors thank Adi Nusser and Marc Davis for useful comments concerning an earlier version of this manuscript, as well as the referee for valuable input. This publication makes use of data products from the 2MASS, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation; the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration and of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We acknowledge the use of the TOPCAT software, http://www.starlink.ac.uk/topcat/ (Taylor 2005). This research was partially supported by the Polish Ministry of Science and Higher Education under grants nos. N N203 0253 33 (M.B. and M.C.) and N N203 509838 (M.B.). Part of this work was carried out within the framework of the European Associated Laboratory “Astrophysics Poland-France” (M.B., M.C., and G.A.M.).|
|Subject Keywords:||cosmology: observations; cosmology: theory; methods: data analysis; methods: statistical; surveys|
|Official Citation:||Is the Two Micron All Sky Survey Clustering Dipole Convergent? Maciej Bilicki et al. 2011 ApJ 741 31|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||06 Dec 2011 16:02|
|Last Modified:||26 Dec 2012 14:34|
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