New limits on microwave background anisotropy at small angular scales

The Very Large Array has been used to examine a small piece of blank sky for possible angular variations in the temperature of the cosmic microwave background. This experiment differs from previous aperture synthesis studies in using a much shorter wavelength, 2 cm instead of 6 cm. As a result, these data yield finer spatial resolution and virtually eliminate radio source contamination, which has complicated the interpretation of the earlier work. The 95 percent confidence limits on sky variance obtained are Delta T/T less than 6.3 x 10 to the -4th with 5.3 arcsec resolution, and Delta T/T less than 1.6 x 10 to the -4th with 18 arcsec resolution. Comparable limits are obtained on polarized fluctuations on 18 arcsec scales. 14 refs.