The roughness of the last scattering surface

Abstract

We propose an alternative analysis of the microwave background temperature anisotropy maps that is based on the study of the roughness of natural surfaces. We apply it to large angle anisotropies, such as those measured by COBE-DMR. We show that for a large signal to noise experiment, the spectral index can be determined independently of the normalization. We then analyze the 4 yr COBE map and find for a flat $\Omega =1$ universe, that the best-fitting value for the spectral index is $n=1.15_{-0.34}^{+0.39}$ and for the amplitude $Q_{rms-PS}=14.1_{-3.5}^{+3.9}\mu K$. For $n=1$, the best-fitting normalization is $Q_{rms-PS}{|}_{n=1}=16.2_{-1.3}^{+1.4}\mu K$.

17 pages, 4 figures (1 in colour), LaTeX, uses aaspp4.sty, ApJ, in press, November 1, 1999 issue, Vol. 525 #1

Cited by in corpus (5)

• The performance of spherical wavelets to detect non-Gaussianity in the CMB sky
• Spherical Mexican Hat wavelet: an application to detect non-Gaussianity in the COBE-DMR maps
• The Cosmic Microwave Background: State of the Art
• Fractal Structure of Isothermal Lines and Loops on the Cosmic Microwave Background
• Cosmic Microwave Background anisotropies: the power spectrum and beyond