Interferometric Imaging of the Sunyaev-Zel'dovich Effect at 30 GHz

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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)

[71.17] Interferometric Imaging of the Sunyaev-Zel'dovich Effect at 30 GHz

Marshall Joy (NASA/MSFC), John E. Carlstrom (Caltech)

The Sunyaev-Zel'dovich effect is a spectral distortion of the cosmic background radiation resulting from inverse-Compton scattering of the microwave photons as they pass through the hot x-ray emitting gas found in the extended atmospheres of clusters of galaxies. The combination of radio measurements of the effect and x-ray measurements of the hot gas offers a potentially powerful probe of the cosmic distance scale. The radio measurements have proven to be difficult, requiring high sensitivity and extensive attention to sources of systematic error. With sensitive interferometric observations one can avoid most sources of systematic error and produce an image of the effect. Most existing interferometers, however, are designed for high angular resolution and thus are not capable of sampling the arcminute and larger angular scales necessary for imaging the Sunyaev-Zel'dovich effect. Our approach is to use an array designed for millimeter-wave observations but outfitted with receivers operating at much longer wavelengths. We built such a system for the mm-array at the Owens Valley Radio Observatory. The receivers cover 8 to 11 mm (36 - 26 GHz) and the projected baselines range from 10.4 to 200 meters, thus making it possible to sample angular scales ranging from 0.1 to 1.9 arcminutes. We describe the design and construction of the instrument, and present first results from observations made in August 1993 of the cluster CL0016+16.

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