Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations:
  Temperature Analysis   We present new full-sky temperature maps in five frequency bands from 23 to
94 GHz, based on the first three years of the WMAP sky survey. The new maps,
which are consistent with the first-year maps and more sensitive, incorporate
improvements in data processing made possible by the additional years of data
and by a more complete analysis of the polarization signal. These include
refinements in the gain calibration and beam response models. We employ two
forms of multi-frequency analysis to separate astrophysical foreground signals
from the CMB, each of which improves on our first-year analyses. First, we form
an improved 'Internal Linear Combination' map, based solely on WMAP data, by
adding a bias correction step and by quantifying residual uncertainties in the
resulting map. Second, we fit and subtract new spatial templates that trace
Galactic emission; in particular, we now use low-frequency WMAP data to trace
synchrotron emission. The WMAP point source catalog is updated to include 115
new sources. We derive the angular power spectrum of the temperature anisotropy
using a hybrid approach that combines a maximum likelihood estimate at low l
(large angular scales) with a quadratic cross-power estimate for l>30. Our best
estimate of the CMB power spectrum is derived by averaging cross-power spectra
from 153 statistically independent channel pairs. The combined spectrum is
cosmic variance limited to l=400, and the signal-to-noise ratio per l-mode
exceeds unity up to l=850. The first two acoustic peaks are seen at l=220.8 +-
0.7 and l=530.9 +- 3.8, respectively, while the first two troughs are seen at
l=412.4 +- 1.9 and l=675.1 +- 11.1, respectively. The rise to the third peak is
unambiguous; when the WMAP data are combined with higher resolution CMB
measurements, the existence of a third acoustic peak is well established.

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The categories of this paper are: dg-ga
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: math-ph