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Session 88 - Cosmic Background Radiation Anisotropies Now and in the Future.
Oral session, Wednesday, January 15
Frontenac Ballroom,

[88.04] Interferometric Observations of the Cosmic Microwave Background

J. E. Carlstrom (U. Chicago)

The ability of interferometric systems to achieve extremely low systematics, directly measure the Fourier transform of the sky, and to provide two dimensional images, make them attractive for ground based observations of Cosmic Microwave Background (CMB) anisotropy. Arcminute scale images of the Sunyaev Zel'dovich Effect have been made with the Ryle Telescope, an array of 13 m telescopes operating at 15 GHz, and also with the OVRO and BIMA millimeter arrays outfitted with cm-wave receivers. The high sensitivity of the images produced by these arrays demonstrate the low systematics inherent in interferometric systems. On larger angular scales (\sim 30^\prime), , the CAT telescope, a prototype array consisting ofthree horns operating at 2 cm, has demonstrated the power of interferometry for imaging the intrinsic CMB anisotropy and determining its power spectrum. There are now three major interferometric systems being built for ground based observations of the CMB on large angular scales. The VSA (Very Small Array, England) will have 15 elements and is designed for \ell spanning 150 to 1200 (1.2 to 0.15 degrees) using two different sets of horns. The VCA (Very Compact Array, U. Chicago) and the CBI (Cosmic Background Imager, Caltech) each will have 13 elements and are designed to complement each other with \ell coverage spanning 160 to 700, and 630 to 3500, respectively. The VSA will be sited in Tenerife, the CBI likely will be deployed on a high dry site in South America, and the VCA will be sited at the South Pole.

In this talk, the basic features of an interferometric system and their applicability to CMB observations will be reviewed. Results from the Sunyaev Zel'dovich imaging observations will be briefly presented. Lastly, the designs and expectations for the VSA, VCA and CBI will be discussed.

Program listing for Wednesday