FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: LIKELIHOODS AND PARAMETERS FROM THE WMAP DATA

Journal Article · Sun Feb 15 00:00:00 EST 2009 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/180/2/306; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21269306

Dunkley, J; Page, L; Jarosik, N ^[1]; Komatsu, E ^[2]; Nolta, M R ^[3]; Spergel, D N ^[4]; Larson, D; Bennett, C L; Gold, B ^[5]; Hinshaw, G; Kogut, A; Wollack, E ^[6]; Weiland, J L; Hill, R S ^[7]; Halpern, M ^[8]; Limon, M ^[9]; Meyer, S S ^[10]; Tucker, G S ^[11]

---

1. Department of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544-0708 (United States)
2. Department of Astronomy, University of Texas, Austin, 2511 Speedway, RLM 15.306, Austin, TX 78712 (United States)
3. Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada)
4. Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544-1001 (United States)
5. Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2686 (United States)
6. Code 665, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
7. Adnet Systems, Inc., 7515 Mission Dr., Suite A100, Lanham, MD 20706 (United States)
8. Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)
9. Columbia Astrophysics Laboratory, 550 W. 120th Street, Mail Code 5247, New York, NY 10027-6902 (United States)
10. Departments of Astrophysics and Physics, KICP and EFI, University of Chicago, Chicago, IL 60637 (United States)
11. Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912-1843 (United States)

This paper focuses on cosmological constraints derived from analysis of WMAP data alone. A simple {lambda}CDM cosmological model fits the five-year WMAP temperature and polarization data. The basic parameters of the model are consistent with the three-year data and now better constrained: {omega} {sub b} h {sup 2} = 0.02273 {+-} 0.00062, {omega} {sub c} h {sup 2} = 0.1099 {+-} 0.0062, {omega}{sub {lambda}} = 0.742 {+-} 0.030, n{sub s} = 0.963{sup +0.014} {sub -0.015}, {tau} = 0.087 {+-} 0.017, and {sigma}{sub 8} = 0.796 {+-} 0.036, with h = 0.719{sup +0.026} {sub -0.027}. With five years of polarization data, we have measured the optical depth to reionization, {tau}>0, at 5{sigma} significance. The redshift of an instantaneous reionization is constrained to be z {sub reion} = 11.0 {+-} 1.4 with 68% confidence. The 2{sigma} lower limit is z {sub reion} > 8.2, and the 3{sigma} limit is z {sub reion} > 6.7. This excludes a sudden reionization of the universe at z = 6 at more than 3.5{sigma} significance, suggesting that reionization was an extended process. Using two methods for polarized foreground cleaning we get consistent estimates for the optical depth, indicating an error due to the foreground treatment of {tau} {approx} 0.01. This cosmological model also fits small-scale cosmic microwave background (CMB) data, and a range of astronomical data measuring the expansion rate and clustering of matter in the universe. We find evidence for the first time in the CMB power spectrum for a nonzero cosmic neutrino background, or a background of relativistic species, with the standard three light neutrino species preferred over the best-fit {lambda}CDM model with N {sub eff} = 0 at >99.5% confidence, and N {sub eff} > 2.3(95%confidence limit (CL)) when varied. The five-year WMAP data improve the upper limit on the tensor-to-scalar ratio, r < 0.43(95%CL), for power-law models, and halve the limit on r for models with a running index, r < 0.58(95%CL). With longer integration we find no evidence for a running spectral index, with dn{sub s} /dln k = -0.037 {+-} 0.028, and find improved limits on isocurvature fluctuations. The current WMAP-only limit on the sum of the neutrino masses is {sigma}m {sub {nu}} < 1.3 eV(95%CL), which is robust, to within 10%, to a varying tensor amplitude, running spectral index, or dark energy equation of state.

• OSTI ID: 21269306
• Journal Information: Astrophysical Journal, Supplement Series, Vol. 180, Issue 2; Other Information: DOI: 10.1088/0067-0049/180/2/306; Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ANISOTROPY
COSMIC NEUTRINOS
COSMOLOGICAL MODELS
COSMOLOGY
EQUATIONS OF STATE
ERRORS
EXPANSION
INDEXES
MASS
NONLUMINOUS MATTER
POLARIZATION
RED SHIFT
RELATIVISTIC RANGE
RELICT RADIATION
UNIVERSE