Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations:
  Final Maps and Results
  We present the final nine-year maps and basic results from the WMAP mission.
We provide new nine-year full sky temperature maps that were processed to
reduce the asymmetry of the effective beams. Temperature and polarization sky
maps are examined to separate CMB anisotropy from foreground emission, and both
types of signals are analyzed in detail. The WMAP mission has resulted in a
highly constrained LCDM cosmological model with precise and accurate parameters
in agreement with a host of other cosmological measurements. When WMAP data are
combined with finer scale CMB, baryon acoustic oscillation, and Hubble constant
measurements, we find that Big Bang nucleosynthesis is well supported and there
is no compelling evidence for a non-standard number of neutrino species
(3.84+/-0.40). The model fit also implies that the age of the universe is
13.772+/-0.059 Gyr, and the fit Hubble constant is H0 = 69.32+/-0.80 km/s/Mpc.
Inflation is also supported: the fluctuations are adiabatic, with Gaussian
random phases; the detection of a deviation of the scalar spectral index from
unity reported earlier by WMAP now has high statistical significance (n_s =
0.9608+/-0.0080); and the universe is close to flat/Euclidean, Omega_k =
-0.0027 (+0.0039/-0.0038). Overall, the WMAP mission has resulted in a
reduction of the cosmological parameter volume by a factor of 68,000 for the
standard six-parameter LCDM model, based on CMB data alone. For a model
including tensors, the allowed seven-parameter volume has been reduced by a
factor 117,000. Other cosmological observations are in accord with the CMB
predictions, and the combined data reduces the cosmological parameter volume
even further. With no significant anomalies and an adequate goodness-of-fit,
the inflationary flat LCDM model and its precise and accurate parameters rooted
in WMAP data stands as the standard model of cosmology.
