Cosmic Microwave Background Radiation Research
The Cosmic Microwave Background (CMB) has a wealth of information about
the origin and evolution of the Universe in its signal. Its spectrum
is that of a blackbody at 2.7 K, confirmation of the prediction
made by the standard Big Bang model. Its angular power spectrum
contains information on the structure that existed at decoupling.
Anisotropy in the matter distribution at this time left imprinted upon
the CMB a small anisotropy (T/T 10) in the
angular distribution of
microwave power. The amplitude and spatial distribution of the
anisotropy are directly related to the conditions in the early Universe
which gave rise to the onset of structure formation. All current models
of structure formation predict specific power spectra and morphologies
for the CMB anisotropy. Within the context of a given theory, the
cosmological parameters such as the Hubble constant H, and
the mass density of the Universe = /, can be
estimated from observations of the anisotropy in the CMB. Determining
the angular power spectrum of the fluctuations, their distribution
function, and imaging the CMB anisotropy at intermediate angular
scales (20 arcseconds to 1 degree)
is the scientific goal of the CARA CMB program.
Measuring the angular power spectrum of the CMB fluctuations, and
producing images of the primary and secondary anisotropy of the CMB,
are key science goals of CARA experiments.
Each experiment addresses a
unique range of angular scales and frequency coverage. Together, they
span a range of angular scales from 3 degrees to 2 arcminutes,
and frequencies from 26 - 400 GHz.
CARA CMB instruments include:
Site characterization information.