Bayesian Analysis Of An Anisotropic Universe Model: Systematics And Polarization

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dc.contributor.utaustinauthorAckerman, Lottyen_US
dc.creatorGroeneboom, Nicolaas E.en_US
dc.creatorAckerman, Lottyen_US
dc.creatorWehus, Ingunn K.en_US
dc.creatorEriksen, Hans Kristianen_US
dc.date.accessioned2016-04-28T22:21:43Z
dc.date.available2016-04-28T22:21:43Z
dc.date.issued2010-10en
dc.description.abstractWe revisit the anisotropic universe model previously developed by Ackerman, Carroll, and Wise (ACW), and generalize both the theoretical and computational framework to include polarization and various forms of systematic effects. We apply our new tools to simulated Wilkinson Microwave Anisotropy Probe (WMAP) data in order to understand the potential impact of asymmetric beams, noise misestimation, and potential zodiacal light emission. We find that neither has any significant impact on the results. We next show that the previously reported ACW signal is also present in the one-year WMAP temperature sky map presented by Liu & Li, where data cuts are more aggressive. Finally, we re-analyze the five-year WMAP data taking into account a previously neglected (-i)(l-l')-term in the signal covariance matrix. We still find a strong detection of a preferred direction in the temperature map. Including multipoles up to l = 400, the anisotropy amplitude for the W band is found to be g = 0.29 +/- 0.031, nonzero at 9 sigma. However, the corresponding preferred direction is also shifted very close to the ecliptic poles at (l, b) = (96, 30), in agreement with the analysis of Hanson & Lewis, indicating that the signal is aligned along the plane of the solar system. This strongly suggests that the signal is not of cosmological origin, but most likely is a product of an unknown systematic effect. Determining the nature of the systematic effect is of vital importance, as it might affect other cosmological conclusions from the WMAP experiment. Finally, we provide a forecast for the Planck experiment including polarization.en_US
dc.description.departmentAstronomyen_US
dc.description.sponsorshipResearch Council of Norwayen_US
dc.description.sponsorshipNASA Office of Space Scienceen_US
dc.identifierdoi:10.15781/T2HN89
dc.identifier.Filename2010_10_bayesian.pdfen_US
dc.identifier.citationGroeneboom, Nicolaas E., Lotty Ackerman, Ingunn Kathrine Wehus, and Hans Kristian Eriksen. "Bayesian analysis of an anisotropic universe model: systematics and polarization." The Astrophysical Journal, Vol. 722, No. 1 (Oct., 2010): 452.en_US
dc.identifier.doi10.1088/0004-637x/722/1/452en_US
dc.identifier.issn0004-637Xen_US
dc.identifier.urihttp://hdl.handle.net/2152/35194
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.rights.restrictionOpenen_US
dc.subjectcosmic background radiationen_US
dc.subjectcosmology: observationsen_US
dc.subjectmethods: numericalen_US
dc.subjectpower spectrum estimationen_US
dc.subjectprobe wmap observationsen_US
dc.subjectinflationaryen_US
dc.subjectuniverseen_US
dc.subjectsky mapsen_US
dc.subjectmicrowaveen_US
dc.subjectcosmologyen_US
dc.subjectscenarioen_US
dc.subjectflatnessen_US
dc.subjecthorizonen_US
dc.subjectarrayen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleBayesian Analysis Of An Anisotropic Universe Model: Systematics And Polarizationen_US
dc.typeArticleen_US

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