Statistical Significance of the Cobe Quadrupole Detection
نویسنده
چکیده
The uncertainties of estimates of cosmic microwave background (CMB) heterogeneity using Cosmic Background Explorer (COBE) data are extremely sensitive to assumptions about the CMB, especially where foreground sources dominate. At 4.5% statistical significance, the COBE least-squares estimate of the CMB quadrupole using data at galactic latitudes lbl > 200 is consistent with a model in which the true quadrupole is zero, and multipoles of degrees 3-20 follow the HarrisonZel'dovich (n = 1) spectrum normalized to the COBE 16tK quadrupole estimate derived from the power spectrum. Most of the uncertainty is due to possible CMB heterogeneity not modelled in the COBE data analysis. Physical constraints on the neglected high frequencies are needed to establish that the COBE estimate is significantly different from zero. Subject heading: cosmic microwave background
منابع مشابه
Microwave anisotropies from texture-seeded structure formation.
The cosmic microwave anisotropies in a scenario of large scale structure formation with cold dark matter and texture are discussed and compared with recent observational results of the COBE satellite. A couple of important statistical parameters are determined. The fluctuations are slightly non gaussian. The quadrupole anisotropy is 1.5±1.2×10−5 and the fluctuations on a angular scale of 10 deg...
متن کاملAnalysis of Spots in the COBE DMR First Year Anisotropy Maps
After the detection of structure in the microwave sky, the characterization of the observed features may be a useful guide to current and future experiments. The first year COBE DMR sky maps were analyzed in order to identify the most significant hot and cold spots. The statistical significance of potential spots of cosmic origin was evaluated with Monte Carlo simulations. The area, eccentricit...
متن کاملTopological Defect Models of Structure Formation after the Cobe Discovery of Cmb Anisotropies
The COBE satellite has discovered anisotropies in the cosmic microwave background (CMB) consistent with a scale invariant spectrum of density perturbations1). As reviewed in this lecture, topological defect models of structure formation generically produce such a spectrum. We give a summary of the cosmic string and global texture models, focusing on distinct observational signatures in large-sc...
متن کاملCobe, Inflation, and Light Scalars
Comparison of the COBE observed quadrupole anisotropy with that predicted in adiabatic CDM models suggests that much of the observed signal may be due to long wavelength gravitational waves. In inflationary models this requires the generation of tensor fluctuations to be at least comparable to scalar density fluctuations. This is feasible, but depends sensitively on the inflaton potential. Alte...
متن کاملGenus and spot density in the COBE DMR rst year anisotropy maps
A statistical analysis of texture on the COBE-DMR rst year sky maps based on the genus and spot number is presented. A generalized 2 statistic is de ned in terms of \observable" quantities: the genus and spot density that would be measured by di erent cosmic observers. This strategy together with the use of Monte Carlo simulations of the temperature uctuations, including all the relevant experi...
متن کامل