| Автор | Cristian Armendariz-Picon |
| Дата выпуска | 2011-03-01 |
| dc.description | A central assumption in our analysis of cosmic structure is that cosmological perturbations have a constant ensemble mean, which can be set to zero by appropriate choice of the background. This property is one of the consequences of statistical homogeneity, the invariance of correlation functions under spatial translations. In this article we explore whether cosmological perturbations indeed have zero mean, and thus test one aspect of statistical homogeneity. We carry out a classical test of the zero mean hypothesis against a class of alternatives in which primordial perturbations have inhomogeneous non-vanishing means, but homogeneous and isotropic covariances. Apart from Gaussianity, our test does not make any additional assumptions about the nature of the perturbations and is thus rather generic and model-independent. The test statistic we employ is essentially Student's t statistic, applied to appropriately masked, foreground-cleaned cosmic microwave background anisotropy maps produced by the WMAP mission. We find evidence for a non-zero mean in a particular range of multipoles, but the evidence against the zero mean hypothesis goes away when we correct for multiple testing. We also place constraints on the mean of the temperature multipoles as a function of angular scale. On angular scales smaller than four degrees, a non-zero mean has to be at least an order of magnitude smaller than the standard deviation of the temperature anisotropies. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Do cosmological perturbations have zero mean? |
| Тип | paper |
| DOI | 10.1088/1475-7516/2011/03/048 |
| Electronic ISSN | 1475-7516 |
| Журнал | Journal of Cosmology and Astroparticle Physics |
| Том | 2011 |
| Первая страница | 48 |
| Последняя страница | 048 |
| Аффилиация | Cristian Armendariz-Picon; Department of Physics, Syracuse University, Syracuse, NY 13244-1130, U.S.A. |
| Выпуск | 03 |
