David N. Spergel - US grants

This theoretical program (analytical and numerical) by a collaboration of investigators from different institutions, is aimed at improving our understanding of the detectability of candidates for the "dark matter" that may make up 90% or more of the matter in the universe. It should help develop experiments for detecting "non-baryonic" dark matter and should make the search for dark matter candidates and other hypothetical but astrophysically relevant non-baryonic particles (e.g. axions, Majorons, familons) more effective. This project should increase the chances of detecting non- luminous, "dark" matter which may make up over 90% of the mass of the universe. Such detection would constitute a major, if not epochal, discovery whose full implications are hard to predict.

Theoretical research will be carried out on the astrophysical implications of new ideas in particle physics. The early universe is thought to have had enormous densities and temperatures. The conditions would provide a natural particle accelerator orders of magnitude more powerful than any conceivable laboratory accelerator. The research will involve looking into the effects of new particles, if they exist, on astrophysical models. Research on the possibility of detecting cosmic strings (trapped remnants of the early universe) existing in our galaxy or in extragalactic environments will be undertaken. The research will be focussed on superconducting cosmic strings, which can carry currents of up to one million billion electron volts. Collaborative research with several experimental groups will center on the possibility of detecting "dark matter" that may comprise 90% of our galaxy. The effects that these particles may have on our Sun and on other stars will be explored. This is a Presidential Young Investigator Award.

Under this award, Princeton University will purchase CONVEX mini- supercomputer facilities for theoretical and observational investigations. Primary use will be for large scale simulations in cosmology to test the currently considered theoretical models against the increasingly detailed observations of large scale structure and the background radiation fields. The local facilities will be used both for preliminary modelling and for manipulation and display of the results obtained from NSF supported supercomputer facilities. Also significant will be use for processing of both optical and radio images. For both applications, the C-220 with its speed, large memory (512 Mb), and efficient FFT routines is ideal. Princeton University is providing 50% of the purchase price in a cost-sharing arrangement.

Ostriker 9318185 The Grand Challenge Application Groups competition provides one mechanism for the support of multidisciplinary teams of scientists and engineers to meet the goals of the High Performance Computing and Communications (HPCC) Initiative in Fiscal Year 1993. The ideal proposal provided not only the opportunity to achieve significant progress on (1) a fundamental problem in science or engineering whose solution could be advanced by applying high performance computing techniques and resources, or (2) enabling technologies which facilitate those advances, but also significant interactions between scientific and computational activities, usually involving mathematical, computer or computational scientist, that would have impact in high performance computational activities beyond the specific scientific or engineering problem area(s) or discipline being studied. This project brings together a balanced, critical mass team of astrophysicists, computational scientists and computer scientists, as well as the technical resources of two NSF supercomputing centers, to mount a focused attack on what is presently one of the most exciting and fundamental problems in the physical sciences: "What is the origin of large-scale structure in the universe and how do galaxies form?" There is abundant observational data sufficient knowledge of the physical laws and mathematical techniques required to understand the origin and evolution of cosmic structure. Yet, it is difficult to confront theory with observation in detail owing to the inherent complexity of these systems and the difficulty of simulating multiple length-scale interactions. However, recent developments in multiscale numerical algorithms by members of our Grand Challenge Application Group (GCAG) and their efficient implementation on scaleable parallel supercomputers should enable the investigators to overcome these limitations. The GCAG will explore the use of: (i) different numerical algorithms (grid-based, particle-based, and hybrid ( grid+particle) to solve the physical equations governing gas, radiation, dark matter and gravity in an expanding universe; (ii) different adaptation strategies (adaptive mesh refinement, hierarchical tree) to achieve efficient, multiscale solvers capable of resolving length scales of interest over 4-6 orders of magnitude; (iii) different programming models (data parallel, SPMD, object parallel) to express these complex, adaptive algorithms in an efficient and portable way on different parallel architectures (TMC's CM5, Intel PARAGON, Cray T3D, Convex MPP) available to the investigators; and (iv) new software technology (e.g. pC++) to develop compilers, optimization designs and performance analysis tools which allow the most efficient implementation of the above strategies in order to expose the various computational and computer science issues required to construct a portable, scaleable application for teraflop systems expected later in this decade. This unique numerical laboratory-will allow the investigators to compare theories of the origin of large-scale structure with the observed universe, to discard incorrect models and hopefully to determine the elements of a viable theory. This HPCC Grand Challenge will be extremely data and UO intensive, pushing current hardware and software systems and solutions to and beyond their limits. The investigators will work with staffs of the Pittsburgh and Illinois supercomputer centers as well as the computer vendors to develop practical and efficient strategies for the storage, visualization and analysis of massive numerical data sets of use to this and other HPCC applications. This award is being supported by the Advanced Projects Research Agency as well as NSF programs in astronomy and computer sciences.

AST-0216105
Draine, Bruce T.

The Principal Investigator and his team will create a powerful parallel-processing facility for research in astrophysics on problems, which do not require "shared memory" or ultra-fast inter-processor communication. Studies will include: Light scattering from irregular interstellar grains, cosmological structure formation, dynamical evolution of gaseous protoplanetary accretion disks, and several other compelling astronomical sciences research topics. The system will contain 96 dual CPU "slave" systems with a total of 192 Central Processing Units, and 192 gigabytes of RAM with a 3.8 TB disk.
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AST-0413793
Spergel

The Joint Dark Energy Mission (JDEM) has recently been created through a cooperative agreement between the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) to detect and characterize dark energy and its influence on the cosmic expansion history. Since ground-based work will impact our understanding of dark energy during the next decade, prior to the launch of JDEM, the constraints which can be expected from such studies should play an explicit role in the requirements definition phase of JDEM. The present project will explore whether and how a ground-based observing campaign could in any way influence the design of, or anticipate any part of the results from, the JDEM. It will assess whether cross-calibration can be precise enough to obviate the need for optical detectors on JDEM, what new instrumentation might be necessary at ground-based facilities, and whether a weak lensing survey from space adds value.

NASA, DOE, and NSF are all devoting significant resources toward detecting and characterizing dark energy, and these investigations provide an excellent opportunity for inter-agency cooperation. Although the NSF will not, and cannot, be involved directly in JDEM itself, the science questions affect the NSF-supported community, and this project will help to define their role.

0530095 Spergel
This Partnership for International Research and Education award will support a multi-institutional partnership between Princeton University, Rutgers University, the University of Pennsylvania, Catolica University (Chile) and the University of KwaZulu-Natal (South Africa) that will address many of the deepest and most pressing questions in cosmology: What is the mysterious dark energy that is the dominant form of energy in the universe? Where are most of the atoms in the universe? How do galaxies and their environments affect each other? These questions will be addressed by a detailed study of a 100 square-degree strip of the Southern sky. Our observations will focus on the universe when it was between 2 and 6 billion years old.

The new Southern African Large Telescope (SALT, in South Africa) will be used to make four-color images of the strip. The Atacama Cosmology Telescope (ACT, in Chile) will make microwave maps of this strip. We will identify galaxy clusters in the strip and then use the SALT spectrograph to obtain ages and redshifts for galaxies in the clusters. The Magellan and Blanco telescopes, also based in Chile, will provide additional high-quality imaging data for a gravitational lensing survey, directly probing the distribution of mass in the survey region. By combining our microwave maps with space-based X-ray observations, we will be able to measure the temperature and distribution of gas and compare it to the spatial distribution of galaxies. An integrated analysis and numerical simulation effort will combine all of the data sets and extract constraints on the universe as a whole and on the evolution of galaxies and clusters.

This ambitious program will build strong international collaborations based on the scientific talents of three major US astronomy and physics programs (Princeton, Rutgers, and the University of Pennsylvania) and of two Southern Hemisphere institutions, Catolica University (Chile) and the University of KwaZulu-Natal (South Africa). This novel multi-national effort will provide superb international scientific training for undergraduates, graduate students, postdoctoral researchers, and young faculty. Undergraduate students will engage in an 8-week international research experience at one of the two Southern Hemisphere sites. Graduate students will be paired with their peers at other partner institutions and will participate in weekly video and web teleconferences. Semi-annual summer schools and workshops (alternating between hemispheres) will introduce graduate students and postdoctoral researchers to cutting-edge technologies, new scientific results, and different cultures. Students, postdoctoral researchers and faculty from other ACT institutions in the UK, Mexico, and Canada will also participate in the summer school, thus broadening the international collaborative network. Postdoctoral researchers and faculty will also travel to South Africa and Chile to work with their colleagues on data collection, analysis, and synthesis. This project will not only enable an exciting scientific research program but will also train future leaders that are able to prosper in the global scientific environment.

AST-0607070
INSTITUTION: Princeton University
PI: Bohdan Paczynski
TITLE: Optical Gravitational Lensing Experiment, Phase III

ABSTRACT

Dr. Bohdan Paczynski, at Princeton University, will continue the Optical Gravitational Lensing Experiment (OGLE). This survey for lensing events typically identifies some 600 events per year, with nearly 3000 events detected to-date. OGLE has identified over 300,000 variable stars, a number of unique extrasolar planets, and has placed important constraints on the presence (or absence) of massive compact halo objects (MACHOS), a proposed type of dark matter in the halo of the Galaxy. Future observations will continue these and other types of discoveries.

The data are released to the broader community, for data mining by professional astronomers, amateur astronomers and students. In particular OGLE is a valuable resource for variable star studies that can be used in a broad range of astrophysical research.

This work is for the acquisition of a high-performance computer cluster for computational astrophysics and for the analysis of data from the Sloan Digital Sky Survey, Wilkinson Microwave Anisotropy Probe, the Atacama Cosmology Telescope, and the Southern Cosmology Survey. The cluster will be available to researchers from several institutions and will be available for the training of students in high-performance computing.

Dr. David Spergel (Princeton University) will use archival measurements of optical dust polarization to 2000 stars in the galactic halo to generate a polarization template map for microwave background studies. Because polarized millimeter and sub-millimeter emission from dust grains is the dominant foreground for cosmic microwave background (CMB) polarization studies, this template will be essential for efforts to detect primordial gravitational waves. The dust polarization measurements will also be used to study the properties of dust grains, to measure the amplitude and spectrum of magnetic field turbulence in the galactic disk and to fix the zero-point of the dust extinction maps.

The dust polarization measurements will help cosmologists working to detect primordial gravitational waves. These gravitational waves were produced during the first moments of the big bang. Their detection would be of broad interest to both scientists and the general public. This research program will lead to the release of dust template maps that will be widely used by many polarization experiments now under development. The improved measurements of the zero-point in dust extinction maps would be widely used in extragalactic studies. This research program will also train undergraduate and graduate students. By engaging students in substantive research, the program will help to develop the next generation of U.S. scientists.

AST-0707731
Spergel

This project is an international collaboration between Princeton University and Institut d'Estudis Espacials de Catalunya (Barcelona, Spain) to develop statistical tools to analyze data from the Atacama Cosmology Telescope (ACT), an NSF-funded telescope in the Atacama Desert of Chile. The techniques, although tuned to the ACT data, will be useful for analyzing any high-resolution Cosmic Microwave Background (CMB) experiment. The first measurements made with these tools will be the power spectrum of temperature fluctuations in the microwave background, and mass fluctuations along the line-of-sight. By combining simulations and analytical theory, the research group will compute the full covariance matrix and its inverse, and compute the likelihood of the observed values for diverse cosmological models. Applying these techniques to the ACT data will improve measurements of the mass density of the Universe, the density of atoms, the properties of the dark energy, and the properties of the neutrino.

Measuring dark energy and dark matter provides insight into fundamental physics and the fate of the universe. Measuring CMB fluctuations and the growth of structure opens a window to the earliest moments of the big bang. These results will likely be of broad popular interest, even as this research trains undergraduate and graduate students in widely applicable statistical techniques, and engages them in a substantive international collaboration. Releasing the user friendly likelihood software along with the data will help a broad group of cosmologists, astrophysicists, and particle physicists.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

Dr Strauss and his team will develop a software pipeline to analyze images from large sky surveys in a systematic way to optimize their use for weak-lensing measurements: light from a distant galaxy is bent by the gravity of all the matter that it passes by on its way to our telescopes, distorting the shape of the galaxy as we see it. The software will characterize the point spread function of the telescope and its variation across the observed field, and analyze multiple exposures of a given field in a self-consistent and statistically rigorous way. The team will both improve measurements of the observed shapes of the 'lensed' galaxies, and experiment with methods to characterize their intrinsic shapes. They will apply their code to raw data from the Canada-France-Hawaii Legacy Survey, which is now public. Their measurement of the weak-lensing signal (an indication of how strongly mass is clumped on the largest scales) will give results completely independent from those of that survey team. These data will enable the study of galaxy properties at redshifts around one, which are seen as they were when the cosmos had expanded to only half its present size, with roughly the same precision as that available at redshifts of only a tenth from the Sloan Digital Sky Survey.

A postdoctoral scholar will be trained by participating in the research. The calibrated photometric catalogs will be made public, with the detailed shape measurements and photometric redshifts. The software tools will also be made public. Both those and the insights gained will be applicable to the next generation of wide-angle surveys, which also aim to measure weak-lensing signals.

The Atacama Cosmology Telescope (ACT) is a project to investigate the Cosmic Microwave Background (CMB) at high angular resolution that was constructed and operated under NSF support over 2005-2010. The ACT facility - a 6m off-axis Gregorian telescope, detectors, and infrastructure - has had two successful seasons of science observations during 2008 and 2009. The awarded project is a follow-on program, called ACTPol, to greatly increase the number and sensitivity of the detectors, and to add linear polarization capability. ACTPol will upgrade and extend instrumentation on the existing telescope, which is located on Cerro Toco (17,030') above the ALMA site on the Chajnator Plateau in Northern Chile. It will address important questions in both basic physics and astrophysics, and if successful will perform transformative research. The program will run for five years. A new bolometer camera with polarization sensitivity will be constructed and used with the ACT for the following science goals: 1) Constrain the initial conditions of universe and measure "running" of scalar spectral index with k; 2) Measure spatial curvature of the universe and dark energy; 3) Discover or constrain the sum of the neutrino masses; 4) Measure the amount of primordial helium; 5) Determine the growth rate of structure; 6) Complement the Planck satellite on smaller angular scales; and 7) Enable future large-scale B-mode polarization measurements.

ACTPol will continue to pursue the types of broader impacts already successfully undertaken by the ACT project. These include a commitment to training students and postdoctoral researchers, continuing strong international partnerships, exchange of technology and personnel with NIST, and outreach to teachers and middle school students, among other activities.

This program will investigate a new technique to explore the ?Hidden Universe? of Dark Matter and Dark Energy. This will be accomplished via determination of the amplitude of matter fluctuations in the universe through measurements of the thermal Sunyaev-Zeldovich effect (the scattering of Cosmic Microwave Background photons off hot gas in galaxy clusters) and gravitational lensing. The proposed technique will be applied to real data from the Atacama Cosmology Experiment, the Planck experiment and the Subaru telescope.

Broader impacts of the work include training of undergraduate and graduate students. In addition, Dr. Spergel has participated in several TV programs on cosmology per year and will continue to do so. He will also continue his program of speaking to elementary school students on measurement and cosmology.

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.