This volume stands as a key general resource for archaeologists working in the region extending from Louisiana through Mississippi north to Missouri and Kentucky, and it represents an opportunity to ...influence for decades a large part of the archaeological work to take place in the Southeast. The book responds to a need for a comprehensive archaeological overview of the Lower Mississippi Valley that forms a portion of an interstate corridor spanning nine states that will run from southern Michigan to the Texas-Mexico border. The culturally sensitive Mississippi Delta is one of the richest archaeological areas in North America, and it is crucial that research designs be comprehensive, coordinated, and meet current preservation and future research needs. The authors are well-respected researchers from both within and outside the region with expertise in the full range of topics that comprise American archaeology. They examine matters of method and theory, the application of materials science, geophysics, and other high-tech tools in archaeology that provide for optimum data-recovery.Contributors:Ian Brown, Kevin L. Bruce, Philip J. Carr, Robert C. Dunnell,James Feathers, Gayle J. Fritz, Michael L. Galaty, S. Homes Hogue, H. Edwin Jackson, Jay K. Johnson, Carl P. Lipo, Hector Neff, Evan Peacock, Janet Rafferty, James H. Turner, John R. Underwood, Amy L. Young
CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the ...origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, \(r\), in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for \(r > 0.003\) at greater than \(5\sigma\), or, in the absence of a detection, of reaching an upper limit of \(r < 0.001\) at \(95\%\) CL.
Opening up a new window of millimeter-wave observations that span frequency bands in the range of 30 to 500 GHz, survey half the sky, and are both an order of magnitude deeper (about 0.5 uK-arcmin) ...and of higher-resolution (about 10 arcseconds) than currently funded surveys would yield an enormous gain in understanding of both fundamental physics and astrophysics. In particular, such a survey would allow for major advances in measuring the distribution of dark matter and gas on small-scales, and yield needed insight on 1.) dark matter particle properties, 2.) the evolution of gas and galaxies, 3.) new light particle species, 4.) the epoch of inflation, and 5.) the census of bodies orbiting in the outer Solar System.
CMB-S4 Decadal Survey APC White Paper Addison, Graeme; Ahmed, Zeeshan; Amin, Mustafa A ...
arXiv (Cornell University),
07/2019
Paper, Journal Article
Odprti dostop
We provide an overview of the science case, instrument configuration and project plan for the next-generation ground-based cosmic microwave background experiment CMB-S4, for consideration by the 2020 ...Decadal Survey.
The Gemini Planet Imager (GPI) is a complex optical system designed to directly detect the self-emission of young planets within two arcseconds of their host stars. After suppressing the starlight ...with an advanced AO system and apodized coronagraph, the dominant residual contamination in the focal plane are speckles from the atmosphere and optical surfaces. Since speckles are diffractive in nature their positions in the field are strongly wavelength dependent, while an actual companion planet will remain at fixed separation. By comparing multiple images at different wavelengths taken simultaneously, we can freeze the speckle pattern and extract the planet light adding an order of magnitude of contrast. To achieve a bandpass of 20%, sufficient to perform speckle suppression, and to observe the entire two arcsecond field of view at diffraction limited sampling, we designed and built an integral field spectrograph with extremely low wavefront error and almost no chromatic aberration. The spectrograph is fully cryogenic and operates in the wavelength range 1 to 2.4 microns with five selectable filters. A prism is used to produce a spectral resolution of 45 in the primary detection band and maintain high throughput. Based on the OSIRIS spectrograph at Keck, we selected to use a lenslet-based spectrograph to achieve an rms wavefront error of approximately 25 nm. Over 36,000 spectra are taken simultaneously and reassembled into image cubes that have roughly 192x192 spatial elements and contain between 11 and 20 spectral channels. The primary dispersion prism can be replaced with a Wollaston prism for dual polarization measurements. The spectrograph also has a pupil-viewing mode for alignment and calibration.
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