This program will upgrade the existing camera on the Atacama Cosmology Telescope in Chile to incorporate new multi-color pixels in large detector arrays at five frequencies, and develop instrumentation to allow wide area measurements of cosmic microwave background (CMB) polarization. This Advanced ACTPol (AdvACT) system will answer questions about the first moments of the universe, the properties of its contents, the formation of structures under the influence of gravity, and the nature of dark energy. In terms of broader impacts, the project will focus on three areas: training graduate and undergraduate students in AdvACT and related science, informing the public, and enhancing the STEM pipeline of students from underrepresented groups through outreach projects. Students and postdoctoral researchers will be involved in the design, assembly, and testing of the new detector arrays. Two summer schools will be hosted coincident with major data releases to train graduate students and postdocs in deriving science from the data. In collaboration with the Franklin Institute, team members will co-produce a new cosmology program and deliver shows at various planetariums. Special efforts will be made to extend research opportunities to undergraduates from groups underrepresented in STEM fields.
The AdvACT intensity and polarization maps of the CMB will 1) overlap the entire Large Synoptic Survey Telescope (LSST) survey as well as other surveys not accessible from the South Pole; 2) have excellent resolution of order one arcminute (depending on frequency); 3) span 25-280 GHz in five bands, essential for the removal of Galactic foregrounds; and 4) have the spatial dynamic range to detect large-angular-scale signatures of inflation at one end, and galaxy clusters and dusty galaxies at the other. AdvACT will perform a large-area survey to search for gravitational waves generated during inflation (B-modes), and measure the isotropy, frequency spectrum, and scale dependence of any detected signal. Measurements of primary CMB fluctuations will improve our knowledge of key cosmological parameters, and measurements of secondary fluctuations will map out the dark matter distribution, potentially providing the first high-signal-to-noise measurement of the sum of the neutrino masses. In addition, AdvACT maps will contain measurements of approximately 20,000 clusters of galaxies via the Sunyaev-Zeldovich Effect, with heightened scientific impact due to overlap of the survey with X-ray and optical surveys such as eROSITA, the Dark Energy Survey, and LSST. AdvACT millimeter-wavelength source lists will provide many thousands of targets for study by ALMA. The program will deliver a number of astronomy community benefits, including public maps, assistance to other teams, and free sharing of technology techniques.
