Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the Universe on Gigaparsec Scales with Remote Cosmic Microwave
  Background Quadrupole Measurements   Scattering of cosmic microwave background (CMB) radiation in galaxy clusters
induces a polarization signal proportional to the CMB quadrupole anisotropy at
the cluster's location and look-back time. A survey of such remote quadrupole
measurements provides information about large-scale cosmological perturbations.
This paper presents a formalism for calculating the correlation function of
remote quadrupole measurements in spherical harmonic space. The number of
independent modes probed by both single-redshift and volume-limited surveys is
presented, along with the length scales probed by these modes. In a remote
quadrupole survey sparsely covering a large area of sky, the largest-scale
modes probe the same length scales as the quadrupole but with much narrower
Fourier-space window functions. The largest-scale modes are significantly
correlated with the local CMB, but even when this correlation is projected out
the largest remaining modes probe gigaparsec scales (comparable to the CMB at
l=2-10) with narrow window functions. These modes may provide insight into the
possible anomalies in the large-scale CMB anisotropy. At fixed redshift, the
data from such a survey form an E-type spin-2 field on the sphere to a good
approximation; the near-absence of B modes will provide a valuable check on
systematic errors. A survey of only a few low-redshift clusters allows an
independent reconstruction of the five coefficients of the local CMB
quadrupole, providing a test for contamination in the WMAP quadrupole. The
formalism presented here is also useful for analyzing smaller-scale surveys to
probe the late integrated Sachs-Wolfe effect and hence the properties of dark
energy

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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: q-bio
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg