ABS The Atacama B-mode Search (ABS) is a new experiment to probe the inflationary epoch in the early universe by measuring the patterns of polarization anisotropy in the cosmic microwave background (CMB) at large angular scales. The polarization of the CMB observed on the celestial sphere can be described with a tensor field. Gravitational waves from inflation, if it occurred, lead to a pseudoscalar component of that tensor field, which is quantified versus angular wavenumber as B-modes [1, 2]. ABS is designed to measure the CMB polarization over a wide frequency band at 145 GHz, using novel detectors optimized for polarization, fabricated at NIST. The detectors are bolometers, based on transition-edge sensors (TES), coupled to feedhorns. ABS features a large focal plane array of detectors illuminated by two ≈ 60 cm mirrors cooled to 4 K. The incoming polarization of the CMB is rotated with a warm half-wave plate (HWP) at the dewar aperture. ABS will make observations at a high-altitude site in the Atacama Desert of Chile.
ACT The goals of the ACT project are to study how the universe began, what it is made of, and how it evolved to its current state. This pursuit is part of the field of scientific cosmology in one which asks questions about the Universe on the largest and grandest scales. Over the past two decades, there has been a tremendous flourishing of the field, driven by many excellent astronomical measurements. This has led to the development of a precise and elegant understanding of cosmology.
PLANCK HFI is an orbital mission designed to make map of the sky in six frequency bands from 100 GHz and 1 THz. This data set will result in cosmic variance limited measurements of the temperature anisotropies out to angular scales beyond the Silk damping tail of the CMB.
QUIET merges members of previous collaborations that have made successful polarization measurements of the CMB. These are: CAPMAP (Princeton, Chicago, Miami, JPL, MPI-Bonn), CBI (Caltech, Oxford), and QUaD (Stanford, Manchester). A group from Columbia, with lots of experience in CMB measurements, and a group from Oslo, with expertise in CMB data processing and analysis, complete the collaboration. Members of the Japanese High Energy Physics Laboratory KEK have recently joined QUIET. This constitutes the first initiative into studies of the CMB in Japan. The group is currently building a setup for testing HEMT detectors and is bringing their extensive experience in data acquisition hardware and software to bear in QUIET. Individuals at Berkeley, Goddard Space Flight Center, and Harvard-Smithsonian have also contributed.
SPIDER is a balloon borne polarimeter borrowing heavily on the combined heritage of the successful BOOMERANG and Bicep experiments, while incorporating antenna coupled TES arrays in the focal plane.
TRUCE is a collaboration of several institutions whose purpose is to design and test exciting next-generation millimeter wave pixels for studies of the Cosmic Microwave Background (CMB). Optimized for observations at 150 GHz, each pixel contains two optically coupled transition edge sensor (TES) bolometers, both sensitive to orthogonal polarization modes. The pixels also boast band-defining filters built into the device. These pixels are slated for use in several upcoming next-generation CMB polarization experiments, including the Atacama B-Mode Search (ABS), the Atacama Cosmology Telescope (ACT)pol, and South Pole Telescope (SPT)pol experiments. To learn more about what our pixels are and how they operate, take a look at the papers below.
WMAP The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA Explorer mission that launched June 2001 to make fundamental measurements of cosmology -- the study of the properties of our universe as a whole. WMAP has been stunningly successful, producing our new Standard Model of Cosmology. WMAP's data stream has ended. Full analysis of the data will be completed in the remaining two years of the mission.