Sunyaev Zel'dovich Effect

The contours show our image of the Sunyaev Zel'dovich Effect, a small spectral distortion of the Cosmic Microwave Background (CMB) intensity caused by its passage through the hot gas associated with a large cluster of galaxies. The false color emission shows the intensity of the x-ray emission from the same hot gas. Data like this allows us to solve for expansion of the universe, the Hubble constant, and also the ratio of ordinary matter to the yet to be determined dark matter in the universe. With the new instrumentation that we plan to use the McDonnell funds to help build, we will be able to search large regions of the sky for distortions in the CMB rather than being limited to special targets identified first by other means, for example by x-ray emission as in this case. The image of the small distortion in the CMB shown here took roughly 10 days to image and yet covers only about one hundredth of square degree of sky. We hope to cover many square degrees of the sky to obtain an accurate inventory of what the universe contains. Like the depth of a shadow, the magnitude of the distortion is not dependent on the distance from us of the object causing the distortion. The new instrumentation will therefore allow us to take inventory of all massive clusters in the universe from the present day to the time from when the CMB radiation was emitted when atoms were first formed roughly 15 billion years ago when the universe was only 300 thousand years old. We plan to combine images spanning those of the early universe which show the seeds of all structure in the universe, to those of the nearby universe, to understand the origin, evolution and ultimate fate of the universe.

--John Carlstrom