The Cosmic Background Imager
The Cosmic Background Imager (CBI) is an instrument designed to make images of the cosmic microwave background radiation and to measure its statistical properties on angular scales from about 3 arc minutes to one degree (spherical harmonic scales from l ˜ 4250 down 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 GHz to 36 GHz. The instantaneous field of view of the instrument is 45 arcmin (FWHM) and its resolution ranges from 3 to 10 arcmin; larger fields can be imaged by mosaicing. At this frequency and resolution, the primary foreground is due to discrete extragalactic sources, which are monitored at the Owens Valley Radio Observatory and subtracted from the CBI visibility measurements. The instrument has been making observations since late 1999 of both primordial CMB fluctuations and the Sunyaev-Zeldovich effect in clusters of galaxies from its site at an altitude of 5080 meters near San Pedro de Atacama, in northern Chile. Observations will continue until August 2001 or later. We present preliminary results from the first few months of observations.
Additional Information© 2005 Astronomical Society of the Pacific. 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 - cosmic_background_imager.pdf
Submitted - 0012212.pdf