## [1005.4549] Relic gravitational waves in the light of 7-year Wilkinson Microwave Anisotropy Probe data and improved prospects for the Planck mission

Authors: D. Baskaran, L. P. Grishchuk, W. Zhao

Date: 25 May 2010

Abstract: The new release of data from Wilkinson Microwave Anisotropy Probe improves the observational situation with relic gravitational waves. The 7-year results enhance the indications of relic gravitational waves in the existing data and change to the better the prospects of confident detection of relic gravitational waves by the currently operating Planck satellite. We apply to WMAP7 data the same methods of analysis that we used earlier [W. Zhao, D. Baskaran, and L.P. Grishchuk, Phys. Rev. D 80, 083005 (2009)] with WMAP5 data. The maximum likelihood value of the quadrupole ratio $R$, which characterizes the amount of relic gravitational waves, increases up to R=0.264, and the interval separating this value from the point R=0 (the hypothesis of no gravitational waves) increases up to a $2\sigma$ level. Assuming that the WMAP7 maximum likelihood set of parameters is correct, the signal-to-noise ratio $S/N$ for the detection of relic gravitational waves by the Planck experiment increases up to $S/N=4.04$, even under pessimistic assumptions with regard to residual foreground contamination and instrumental noises. We comment on theoretical frameworks that, in the case of success, will be accepted or decisively rejected by the Planck observations.

#### Jun 01, 2010

1005.4549 (/preprints)
2010-06-01, 12:30