This award is to support measurements of the 14-billion-year cosmic microwave background (CMB) light with the South Pole Telescope (SPT) to address some of the most basic and compelling questions in cosmology: What is the origin of the Universe? What is the Universe made of? What is the mass scale of the neutrinos? When did the first stars and galaxies form and how was the Universe reionized? What is the Dark Energy that is accelerating the expansion of the Universe? The SPT plays a unique role in the pursuit of these questions. Its siting is ideal for ultra-low-noise imaging surveys of the sky at the millimeter and sub-millimeter radio wavelengths. The SPT is supported by the NSF's Amundsen-Scott South Pole Station, which is the best operational site on Earth for mm-wave sky surveys. This unique geographical location allows SPT to obtain extremely sensitive 24/7 observations of targeted low Galactic foreground regions of the sky.
The telescope's third-generation, SPT-3G receiver has 16,000 detectors configured for polarization-sensitive observations in three millimeter-wave bands. The proposed operation includes five years of sky surveys to obtain ultra-deep measurements of a 1500 square degree field and to produce and publicly archive essential data products from the survey. The telescope's CMB temperatures and polarization power spectrum will play a central role in probing the nature of current tensions among cosmological parameter estimations from different data sets and determining if their explanation requires physics beyond the current LCDM model. The data will help constraining the Dark Energy properties that affect the growth of large structures through both the CMB lensing and abundance of galaxy clusters. The proposed operations also support SPT's critical role in the Event Horizon Telescope (EHT), a global array of telescopes to image the event horizon around the black hole at the center of Milky Way Galaxy. This award addresses and advances the science objectives and goals of the NSF's "Windows on the Universe: The Era of Multi-Messenger Astrophysics" program.
The proposed research activity will also contribute to the training of the next generation of scientists by integrating graduate and undergraduate education with the technology development, astronomical observations, and scientific analyses of SPT data. Research and education are integrated by bringing research activities into the undergraduate classroom and sharing of forefront research with non-scientists extending it beyond the university through a well-established educational network that reaches a wide audience at all levels of the educational continuum. Through museum partnerships and new media, the SPT outreach and educational efforts reach large numbers of individuals while personalizing the experience.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
