DIRECTIONAL DEPENDENCE OF {Lambda}CDM COSMOLOGICAL PARAMETERS
- Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway)
- Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France)
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.
- OSTI ID:
- 22140251
- Journal Information:
- Astrophysical Journal Letters, Vol. 773, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
Needlet detection of features in the WMAP CMB sky and the impact on anisotropies and hemispherical asymmetries
Anomalous CMB north-south asymmetry