Directional dependence of CDM cosmological parameters
Mar 21, 20135 pages
Published in:
- Astrophys.J.Lett. 773 (2013) L3
- Published: Jul 24, 2013
e-Print:
- 1303.5371 [astro-ph.CO]
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Abstract: (IOP)
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 3.4σ 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 As, ns, and Ωbare the most sensitive to this power asymmetry. In particular, for the two opposite hemispheres aligned with the preferred asymmetry axis, we find ns= 0.959 ± 0.022 and ns= 0.989 ± 0.024, respectively.Note:
- 6 pages, 7 figures, published in ApJL
- cosmic background radiation
- cosmology: observations
- methods: statistical
References(27)
Figures(7)