The Berkeley-Illinois-Maryland-Association (BIMA) Array has been
used with cm-wave receivers to conduct a survey of ten
independent fields in order to place limits on secondary
Cosmic Microwave Background (CMB) anisotropy. Current
measurements indicate a level of excess power that excludes
the effects of instrumental noise by better than 95%
confidence. The most
likely source of these fluctuations in the CMB is believed
to be the Sunyaev-Zel'dovich (SZ) effect (see
Observations of clusters with the SZ effect ).
Follow-up observations are planned in order to determine
whether the sources of excess power in the BIMA fields
are indeed clusters of galaxies.
The BIMA instrument is based out of
the Radio Astronomy Laboratory at U.C. Berkeley,
the Laboratory for Astronomical Imaging at U. Illinois
at Urbana, and
Laboratory for Millimeter-Wave Astronomy at U. Maryland.