skip to main content

SciTech ConnectSciTech Connect

Title: DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS

We study hemispherical power asymmetry in the Wilkinson Microwave Anisotropy Probe 9 yr data. We analyze the combined V- and W-band sky maps, after application of the KQ85 mask, and find that the asymmetry is statistically significant at the 3.4{sigma} confidence level for l = 2-600, where the data are signal-dominated, with a preferred asymmetry direction (l, b) = (227, -27). Individual asymmetry axes estimated from six independent multipole ranges are all consistent with this direction. Subsequently, we estimate cosmological parameters on different parts of the sky and show that the parameters A{sub s} , n{sub s} , and {Omega}{sub b} are the most sensitive to this power asymmetry. In particular, for the two opposite hemispheres aligned with the preferred asymmetry axis, we find n{sub s} = 0.959 {+-} 0.022 and n{sub s} = 0.989 {+-} 0.024, respectively.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)
  2. Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)
  3. Jet Propulsion Laboratory, M/S 169/327, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
Publication Date:
OSTI Identifier:
22140251
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 773; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; ASYMMETRY; BACKGROUND RADIATION; COSMOLOGICAL CONSTANT; COSMOLOGY; MICROWAVE RADIATION; PROBES