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"First-year Wilkinson Microwave
Anisotropy (WMAP) observations: Preliminary maps and basic results,"
Charles
L. Bennett and 20 others, Astrophysical Journal Supplement Series,
148(1): 1-27, September 2003.
[Authors' affiliations: 10 U.S. and Canadian
institutions]
Abstract: "We present full-sky
microwave maps in five frequency bands (23-94 GHz) from the Wilkinson
Microwave Anisotropy Probe (WMAP) first-year sky survey.
Calibration errors are less than 0.5%, and the low systematic error
level is well specified. The cosmic microwave background (CMB) is separated
from the foregrounds using multifrequency data. The sky maps are consistent
with the 7degrees FWHM Cosmic Background Explorer (COBE) maps. We report more
precise, but consistent, dipole and quadrupole values. The CMB anisotropy
obeys Gaussian statistics with -58<f(NL)<134 (95% confidence level
[CL]). The 2&LE;l&LE;900 anisotropy power spectrum is
cosmic-variance-limited for l<354, with a signal-to-noise ratio greater
than 1 per mode to l=658. The temperature-polarization cross-power spectrum
reveals both acoustic features and a large-angle correlation from reionization.
The optical depth of reionization is tau=0.17+/-0.04, which implies a
reionization epoch of t(r)=180(-80)(+220) Myr (95% CL) after the big bang at a
redshift of z(r)=20(-9)(+10) (95% CL) for a range of ionization scenarios.
This early reionization is incompatible with the presence of a significant
warm dark matter density.
"A best-fit cosmological model to the
CMB and other measures of large-scale structure works remarkably well with
only a few parameters. The age of the best-fit universe is t(0)=13.7+/-0.2 Gyr.
Decoupling was t(dec)=379(-7)(+8) kyr after the big bang at a redshift of
z(dec)=1089+/-1. The thickness of the decoupling surface was Deltaz(dec)=195+/-2.
The matter density of the universe is Omega(m)h(2)=0.135(-0.009)(+0.008), the
baryon density is Omega(b)h(2)=0.0224+/-0.0009, and the total mass-energy of
the universe is Omega(tot)=1.02+/-0.02. It appears that there may be
progressively less fluctuation power on smaller scales, from WMAP to
fine-scale CMB measurements to galaxies and finally to the Lyalpha forest.
This may be accounted for with a running spectral index of scalar
fluctuations, fitted as n(s)=0.93+/-0.03 at wavenumber k(0)=0.05 Mpc(-1) (l(eff)approximate
to700), with a slope of dn(s)/d ln k=-0.031(-0.018)(+0.016) in the best-fit
model. (For WMAP data alone, n(s)=0.99+/-0.04.) This flat universe model is
composed of 4.4% baryons, 22% dark matter, and 73% dark energy. The dark
energy equation of state is limited to w<-0.78 (95% CL). Inflation theory
is supported with n(s)&AP;1, &UOmega;(tot)&AP;1, Gaussian random
phases of the CMB anisotropy, and superhorizon fluctuations implied by the
temperature-polarization anticorrelations at decoupling. An admixture of
isocurvature modes does not improve the fit. The tensor-to-scalar ratio is
r(k(0)=0.002 Mpc(-1))<0.90 (95% CL). The lack of CMB fluctuation power on
the largest angular scales reported by COBE and confirmed by WMAP
is intriguing. WMAP continues to operate, so results will
improve."
This 2003 paper from Astrophysical Journal
Supplement Series was cited 71 times in current journal
articles indexed by Thomson Scientific during November-December 2004. For the
fifth bimonthly count in a row, this report emerges as the second-most-cited
physics papers published in the last two years, aside from reviews. Prior to
the most recent two-month count, citations to the paper have accrued as
follows:
September-October 2004: 84 citations
July-August 2004: 82
May-June 2004: 58
March-April 2004: 50
January-February 2004: 52
November-December 2003: 33
September-October 2003: 22
Total citations to date: 452
with Charles
L. Bennett
SOURCE: Hot
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