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Constraints on cosmic hemispherical power anomalies from quasars

Hirata, Christopher M. (2009) Constraints on cosmic hemispherical power anomalies from quasars. Journal of Cosmology and Astroparticle Physics, 2009 (9). Art. No. 011 . ISSN 1475-7516. http://resolver.caltech.edu/CaltechAUTHORS:20091102-093731579

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Abstract

Recent analyses of the cosmic microwave background (CMB) maps from the WMAP satellite have uncovered evidence for a hemispherical power anomaly, i.e. a dipole modulation of the CMB power spectrum at large angular scales with an amplitude of ±14 percent. Erickcek et al have put forward an inflationary model to explain this anomaly. Their scenario is a variation on the curvaton scenario in which the curvaton possesses a large-scale spatial gradient that modulates the amplitude of CMB fluctuations. We show that this scenario would also lead to a spatial gradient in the amplitude of perturbations σ8, and hence to a dipole asymmetry in any highly biased tracer of the underlying density field. Using the high-redshift quasars from the Sloan Digital Sky Survey, we find an upper limit on such a gradient of |∇σ8|/σ8 < 0.027r_(lss)^(−1) (99% posterior probability), where r_(lss) is the comoving distance to the last-scattering surface. This rules out the simplest version of the curvaton spatial gradient scenario.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/1475-7516/2009/09/011 DOIUNSPECIFIED
http://www.iop.org/EJ/abstract/1475-7516/2009/09/011/PublisherUNSPECIFIED
http://arxiv.org/abs/0907.0703arXivUNSPECIFIED
Additional Information:© 2009 IOP Publishing Ltd and SISSA. Received July 17, 2009. Accepted August 27, 2009. Published September 8, 2009. CH wishes to thank Y Shen for providing his quasar sample and associated mask files. CH also wishes to thank A Erickcek, M Kamionkowski, and Y Shen for their useful comments on the paper. CH is supported by the US Department of Energy under contract DE-FG03-02-ER40701, the National Science Foundation under contract AST-0807337, and the Alfred P Sloan Foundation. Funding for the Sloan Digital Sky Survey (SDSS) and SDSS-II has been provided by the Alfred P Sloan Foundation, the Participating Institutions, the National Science Foundation, the US Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, and the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, The University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.
Group:TAPIR
Funders:
Funding AgencyGrant Number
US Department of EnergyDE-FG03-02-ER40701
NSFAST-0807337
Alfred P. Sloan FoundationUNSPECIFIED
Participating InstitutionsUNSPECIFIED
NASAUNSPECIFIED
Japanese MonbukagakushoUNSPECIFIED
Max Planck SocietyUNSPECIFIED
Higher Education Funding Council for EnglandUNSPECIFIED
Subject Keywords:cosmological parameters from LSS; inflation; non-gaussianity
Record Number:CaltechAUTHORS:20091102-093731579
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20091102-093731579
Official Citation:Title: Constraints on cosmic hemispherical power anomalies from quasars Author(s): Christopher M. Hirata Publication Date: September 2009 Volume: 2009 Start Page: 011 Publication: Journal of Cosmology and Astroparticle Physics Abstract: Recent analyses of the cosmic microwave background (CMB) maps from the WMAP satellite have uncovered evidence for a hemispherical power anomaly, i.e. a dipole modulation of the CMB power spectrum at large angular scales with an amplitude of +-14 percent. Erickcek et al have put forward an inflationary model to explain this anomaly. Their scenario is a variation on the curvaton scenario in which the curvaton possesses a large-scale spatial gradient that modulates the amplitude of CMB fluctuations. We show that this scenario would also lead to a spatial gradient in the amplitude of perturbations s8, and hence to a dipole asymmetry in any highly biased tracer of the underlying density field. Using the high-redshift quasars from the Sloan Digital Sky Survey, we find an upper limit on such a gradient of |[?]s8|/s8 &lt; 0.027rlss[?]1 (99% posterior probability), where rlss is the comoving distance to the last-scattering surface. This rules out the simplest version of the curvaton spatial gradient scenario.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16534
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:02 Nov 2009 20:16
Last Modified:26 Dec 2012 11:31

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