Likelihood Analysis of Degree-Scale Anisotropy Experiments Compared with COBE

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Session 71 -- Galaxy and CBR Distribution
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[71.15] Likelihood Analysis of Degree-Scale Anisotropy Experiments Compared with COBE

E. L. Wright, M. Rubin (UCLA)

Comparing the large angular scale $\Delta T$ observed by the {\sl COBE} DMR experiment to the $\Delta T$ observed by balloon and ground-based experiments at degree scales is one of the best ways to test the inflationary scenario through its prediction of (almost) equal power on all scales. We have computed likelihood functions for the Schuster et al. (1993) South Pole (SP91) $\Delta T$ data on $1^\circ$ scales given models based on the Holtzman (1989) calculations scaled by a linear bias factor. Our calculations explicitly include the sinusoidal chop and the linear baseline removal used in this experiment. While our results confirm the result based on a simple analysis assuming that SP91 is a single subtracted experiment with a 1.5$^\circ$ FWHM Gaussian beam and a 2.1$^\circ$ square-wave chop that the maximum likelihood for SP91 is given by a bias factor roughly twice as large as the bias needed to match the COBE large-scale $\Delta T$, we have used the joint likelihood of the COBE $\Delta T$ at $\ell \approx 4$ (taken from Wright et al. 1994) and the SP91 data at $\ell \approx 44$ to compute limits on the spectral index $n$ of the power spectrum of primordial perturbations $P(k) \propto k^n$. A similar analysis using the results of the MAX experiment at $\ell \approx 110$ will also be given.

{The National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) is responsible for the design, development, and operation of the Cosmic Background Explorer (COBE). Scientific guidance is provided by the COBE Science Working Group. final GSFC is also responsible for the development of the analysis software and for the production of the mission data sets.}

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