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K.S. Dawson, W.L. Holzapfel (UC Berkeley), J.E. Carlstrom, S.J. LaRoque, A.D. Miller, D. Nagai (U. of Chicago), M. Joy (Space Science Laboratory, NASA MSFC)
We report new results from an ongoing experiment to measure the power spectrum of Cosmic Microwave Background (CMB) anisotropy with the BIMA array. We observe in a compact configuration to maximize temperature sensitivity on angular scales of approximately two arcminutes. On these angular scales, secondary anisotropies such as the Sunyaev Zel'dovich effect in clusters of galaxies are expected to dominate the CMB power spectrum. Observation of the CMB at arcminute scales therefore has the potential to serve as a powerful probe for structure formation in the universe. We have accumulated over 600 hours of integration with the BIMA array during three summers of observation. The sample consists of ten independent fields, selected from NVSS and IRAS images to lie in regions free of bright radio point sources and infrared contrast. Observations cover approximately 0.1 square degrees of sky at an RMS temperature sensitivity of 15 \muK for a two arcminute synthesized beam. With concurrent observations from the VLA at 4.8 GHz, we have identified point sources which could act as contaminants to estimates of the CMB power spectrum and removed them from the analysis. Assuming a flat band power model for the CMB power spectrum, we find \Delta T=16.6+5.3-5.9 \muK at 68% confidence for CMB power described by an average multipole of \ell=5237. We provide a second point in the power spectrum corresponding to higher angular resolution. For CMB flat band power described by an average multipole of \ell=8748, we find \Delta T<26.5 \muK at 95% confidence.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.