First Results from the CBI
The Cosmic Background Imager (CBI) is an instrument designed to measure intrinsic anisotropies in the cosmic microwave background (CMB) on angular scales from about 3 arc minutes to one degree (spherical harmonics of l~4250 to l~400). The CBI is a 13 element interferometer mounted on a 6 meter platform operating in ten 1-GHz frequency bands from 26 to 36 GHz. We present a review of the capabilities of the instrument and a discussion of observations which have been taken over the past year from the Atacama desert of Chile. We also present first results from the CBI which show a strong cutoff in the power spectrum between l=600 and l=1200 which is consistent with the photon-diffusive damping predicted by most models of structure formation in the early universe. We discuss future topics which the CBI will address.
Additional Information© 2001 American Institute of Physics. Issue Date: 15 October 2001. We are grateful for the contributions to this project of our collaborators: Russ Keeney, Steve Miller, Walter Schaal, and John Yamasaki (Caltech); John Carlstrom and Erik Leitch (University of Chicago); Bill Holzapfel (University of California, Berkeley); Steven Myers (National Radio Astronomy Observatory); Marshall Joy (NASA's Marshall Space Flight Center); Angel Otarola (European Southern Observatory); and Leonardo Bronfman, Jorge May, Simon Casassus, and Pablo Altamirano (University of Chile). The CBI project has been supported by the National Science Foundation under grants AST-9413935 and AST-9802989, and we are also grateful for the generous support of Maxine and Ronald Linde, Cecil and Sally Drinkward, and our colleagues at the California Institute of Technology, especially the Provost, the President, and the Chairman of the Division of Physics, Mathematics, and Astronomy. We are grateful to CONICYT for permission to operate the CBI in the Chajnantor Scientific Preserve in Chile. JS and PSU acknowledge support from National Science Foundation Graduate Student Fellowships.
Published - MASaipcp01.pdf