Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modelling the WMAP large-angle anomalies as an effect of a local density
  inhomogeneity   We investigate large-angle scale temperature anisotropy in the Cosmic
Microwave Background (CMB) with the Wilkinson Microwave Anisotropy Probe (WMAP)
data and model the large-angle anomalies as the effect of the CMB quadrupole
anisotropies caused by the local density inhomogeneities. The quadrupole caused
by the local density inhomogeneities is different from the special relativity
kinematic quadrupole. If the observer inhabits a strong inhomogeneous region,
the local quadrupole should not be neglected. We calculate such local
quadrupole under the assumption that there is a huge density fluctuation field
in direction $(284^{\circ},74^{\circ})$, where the density fluctuation is
$10^{-3}$, and its center is $\sim 112h^{-1} \rm {Mpc}$ away from us. After
removing such mock signals from WMAP data, the power in quadrupole, $C_2$,
increases from the range $(200\sim260\mu \rm{K^2})$ to $\sim1000\mu \rm{K^2}$.
The quantity S, which is used to estimate the alignment between the quadrupole
and the octopole, decreases from $(0.7\sim0.74)$ to $(0.31\sim0.37)$, while the
model predict that $C_2=1071.5\mu \rm{K^2}$, $S=0.412$. So our local density
inhomogeneity model can, in part, explain the WMAP low-$\ell$ anomalies.

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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: eess
33
The categories of this paper are: plasm-ph