For refcode 2007ApJS..170..288H: Retrieve 324 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by American Astronomical Society.
Reproduced by permission
2007ApJS..170..288H
ThreeYear Wilkinson Microwave Anisotropy Probe (WMAP) Observations:
Temperature Analysis
Hinshaw, G.; Nolta, M. R.; Bennett, C. L.; Bean, R.; Dore, O.; Greason, M.
R.; Halpern, M.; Hill, R. S.; Jarosik, N.; Kogut, A.; Komatsu, E.; Limon,
M.; Odegard, N.; Meyer, S. S.; Page, L.; Peiris, H. V.; Spergel, D. N.;
Tucker, G. S.; Verde, L.; Weiland, J. L.; Wollack, E.; Wright, E. L.
Abstract. We present new fullsky temperature maps in five frequency bands
from 23 to 94 GHz, based on data from the first 3 years of the WMAP sky
survey. The new maps are consistent with the firstyear maps and are more
sensitive. The 3 year maps incorporate several improvements in data
processing made possible by the additional years of data and by a more
complete analysis of the polarization signal. These include several new
consistency tests as well as refinements in the gain calibration and beam
response models. We employ two forms of multifrequency analysis to separate
astrophysical foreground signals from the CMB, each of which improves on
our firstyear analyses. First, we form an improved "Internal Linear
Combination" (ILC) map, based solely on WMAP data, by adding a
biascorrection 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 lowfrequency WMAP data to
trace synchrotron emission instead of the 408 MHz sky survey. The WMAP
point source catalog is updated to include 115 new sources whose detection
is made possible by the improved sky map sensitivity. 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 crosspower estimate for l>30. The resulting multifrequency
spectra are analyzed for residual point source contamination. At 94 GHz the
unmasked sources contribute 128+/27 {mu}K^2^ to l(l+1)C_l_/2{pi} at l=1000.
After subtracting this contribution, our best estimate of the CMB power
spectrum is derived by averaging crosspower spectra from 153 statistically
independent channel pairs. The combined spectrum is cosmic variance limited
to l=400, and the signaltonoise ratio per lmode exceeds unity up to
l=850. For bins of width {DELTA}l/l=3%, the signaltonoise ratio exceeds
unity up to l=1000. 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=675.2+/11.1. 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.
Spergel et al. use the 3 year temperature and polarization data to
constrain cosmological model parameters. A simple sixparameter {lambda}CDM
model continues to fit CMB data and other measures of largescale structure
remarkably well. The new polarization data produce a better measurement of
the optical depth to reionization, {tau}=0.089+/0.03. This new and tighter
constraint on {tau} helps break a degeneracy with the scalar spectral index,
which is now found to be n_s_=0.960+/0.016. If additional cosmological
data sets are included in the analysis, the spectral index is found to be
n_s_=0.947+/0.015.
Key words: Cosmology: Cosmic Microwave Background, Cosmology: Observations,
Cosmology: Dark Matter, Cosmology: Early Universe, Instrumentation:
Detectors, Space Vehicles: Instruments, Telescopes
Retrieve 324 NED objects in this reference. Please click here for ADS abstract
