Exterior view of Keck Array in its three-receiver configuration. The
elevated station is seen in the distance. Photo courtesy of winter-over
Robert Schwarz.
All-sky maps of expected levels of
polarized foregrounds at 150 GHz. The projections are centered on RA,dec
= (0,0). The ~800 square degree BICEP2/Keck Array target field is shown in
red outline; the white outline is the aggregate boundary of all
similarly-sized fields in these template maps in which either synchrotron
or dust contamination is as low as in the BICEP2/Keck Array field.
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Keck Array Overview Keck Array is a new telescope in the BICEP/BICEP2/Keck Array program of experiments. It consists of multiple receivers very similar to BICEP2 placed on the telescope mount originally built for the DASI experiment. In the 2010-2011 austral summer, the first three receivers tuned to 150 GHz were installed. The program benefits from the infrastructure provided by the Martin A. Pomerantz Observatory (MAPO) at the South Pole Station, Antarctica. Unlike BICEP2, the Keck Array detectors are kept cryogenically cold by a pulse tube refrigerator in an effort to reduce the need to import liquid cryogens to the South Pole in the future. Additional receivers are planned to be installed next summer. The scientific objective is the same as BICEP2 − to attempt to measure B-mode polarization of the cosmic microwave background (CMB). Keck Array searches on medium to large angular scales, where B-mode polarization induced by gravitational waves is hypothesized to be larger than similar patterns on smaller angular scales due to gravitational lensing. A positive detection of B-mode polarization could be direct evidence for the theory of cosmic inflation or an alternative model. Finding evidence of inflation is one of the highest priorities in cosmology today. |