Astronomy and Astrophysics
Chairman's Introduction, Edward "Rocky" Kolb | Faculty Research Summaries
In the Department of Astronomy and Astrophysics at the University of Chicago researchers are actively pursuing the understanding of the cosmos in all scales, from the solar system to the universe as a whole. Topics cover a broad range including the history of astronomy, the physics of the Sun and solar-like stars, the origin of cosmic rays, the origin of meteorites and comets, the structure and dynamics of interstellar matter, the birth of stars, the death of stars, the origin of the elements, high energy and relativistic astrophysics, the origins and dynamics of galaxies, the origin of structure in the universe, particle astrophysics, and cosmology. The activities involve theoretical, experimental, and observational programs among a community of faculty members from the Departments of Astronomy and Astrophysics, Physics, Chemistry, and History, the Enrico Fermi Institute, the Argonne National Laboratory, and the Fermi National Accelerator Laboratory.
Faculty in our Department are involved in a number of ground-breaking efforts including the Sloan Digital Sky Survey (SDSS), the Degree Angular Scale Interferometer (DASI), the Sunyaev-Zel'dovich Array (SZA), the Wilkinson Microwave Anisotropy Probe (WMAP), the TopHat balloon experiment, the Very Energetic Radiation Imaging Telescope Array System (VERITAS), the Stratospheric Observatory for Infrared Astronomy (SOFIA), the Pierre Auger Project, the Far Ultraviolet Spectroscopic Explorer (FUSE), the High Energy Transient Explorer (HETE-2), the Very Long Baseline Array (VLBA), and the Hubble Space Telescope (HST). Next generation projects presently under development include the South Pole Telescope (SPT) and the Extragalactic Diffuse Emission Experiment (EDGE). Our faculty are leading researchers in three National Science Foundation's Frontier Centers: the Kavli Institute for Cosmological Physics (KICP), the Center for Magnetic Self-Organization in Astrophysical and Laboratory Plasmas, and the Center for Nuclear Astrophysics and one DOE Center: the ASC/Alliances Center for Astrophysical Thermonuclear Flashes (Flash Center).
The Kavli Institute for Cosmological Physics is at the forefront of research that exploits the connections between the physics in the smallest scales, the scale of interactions of quarks and leptons, to the birth and evolution of the universe on the largest scales. Faculty in the KICP are involved the SDSS, DASI, SZA, WMAP, TopHat, VERITAS, the Pierre Auger Project, EDGE, and the new SPT. The Center brings together top experimentalists and observers with foremost theorists of cosmology and particle physics. Faculty in the KICP includes J. Carlstrom, J. Cronin, J. Frieman, A. Kravtsov, W. Hu, A. Olinto, C. Pryke, S. Swordy, and M. Turner.
The ASC Flash Center is developing the leading numerical simulations of Astrophysical Explosions to understand transient phenomena from novae and supernovae to gamma-ray bursts. They have completed large scale 2-d and 3-d simulations of wind-wave mixing that apply to nova models, and large scale 3-d simulations of the deflagration of a Chandrasekhar mass white dwarf. Faculty who are involved in this effort include A. Khoklov, D. Lamb, R. Rosner, and J. Truran.
The Center for Magnetic Self-Organization in Astrophysical and Laboratory Plasmas is a joint effort between the University of Chicago, the Princeton University Plasma Physics Laboratory, and the University of Wisconsin, Madison. The Center studies the interaction of magnetic fields and ionized fluids in both astrophysical and terrestrial laboratories and the lead faculty at Chicago is R. Rosner.
The Center for Nuclear Astrophysics is a new multi-institution NSF Frontier Center that will focus in the overlap between nuclear physics and astrophysics. This Center will play a key role in the future of the Rare Isotope Accelerator (RIA). J. Truran leads the effort at Chicago and at the Argonne National Laboratory.
The Sloan Digital Sky Survey is the most comprehensive survey of the sky yet undertaken. Begun in April 2000, the survey is mapping in detail one-sixth of the entire sky. When completed in June 2005, it will have determined the positions, brightness, and colors of nearly 100 million celestial objects (mostly galaxies as well as stars in our own galaxy). It will also measure the distances (redshifts) to roughly 600,000 galaxies and nearly 100,000 quasars. The first data set was released to the public in June 2003. Over 250 scientific publications have been based on results from the SDSS.
The Sunyaev-Zel'dovich Array (SZA) started construction in the High Bay area of the Fermi Institutes under the leadership of J. Carlstrom and C. Pryke. This new array consists of eight 3.5 m dishes, and is optimized for the detection of high redshift galaxy clusters. The SZA will map clusters of galaxies using the Sunyaev-Zel'dovich effect aiming at the study of the mysterious dark energy component of the universe.
The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a major ground-based gamma-ray observatory now under construction. It will consist of an array of seven 10m to 12m optical reflectors for gamma-ray astronomy in the GeV to TeV energy range. The prototype of this very high-energy telescope was built in the High Bay area under the leadership of Prof. Simon Swordy and shipped to the observing site this past spring.
SOFIA is an airborne observatory that will study the universe in the infrared spectrum. The HAWC (High-resolution Airborne Wideband Camera) camera for SOFIA is under construction at Yerkes under the leadership of A. Harper and R. Hildebrand.
The Pierre Auger Project is the largest telescope to study the highest energy particles. Lead by J. Cronin, the observatory has deployed 150 tanks of the planned 1600 tank array and has installed 2 of the 4 fluorescence observatories in the Mendoza province in Argentina. The Auger Observatory in the Southern Hemisphere together with a future Northern Hemisphere twin should discover the mysterious origin of the highest energy particles ever to be observed.
The South Pole Telescope has been approved by the National Science Board. This multi-institutional team of scientists led by J. Carlstrom will build a telescope at the South Pole aimed at piercing one of the darkest secrets of the universe: why the universe is accelerating.
In addition to the many projects outlined above, the students and faculty in the Department have access to a 3.5-meter aperture telescope observational facility located at Apache Point Observatory in New Mexico. This telescope has been designed to permit routine remote observing and rapid changeover between instruments. A very high resolution Echelle Spectrograph was built by a team led by faculty member R. Hildebrand. It allows Chicago researchers to determine the composition of stars nearby and to probe the Universe at a time before stars and galaxies existed. Adaptive optics are being developed for the telescope, which will enable faint objects to be studied with a resolution of 0.1 arcsecond. Our instrumentation efforts are developed both at the Chicago campus and at the Yerkes Observatory, located in Williams Bay, Wisconsin. Yerkes Observatory serves as a laboratory for development of the instruments and techniques to be used on major telescopes, including the 3.5-meter telescope, the Stratospheric Observatory for Infrared Astronomy (SOFIA), and the Infrared Telescope Facility. Yerkes also provides a continuing observational program, with its famous 40-inch (1-meter) refractor and its 41-inch (1-meter) and 0.6-meter reflectors.
Recent findings worth highlighting are the discovery of the polarization of the Cosmic Microwave Background by DASI and maps of the CMB sky by WMAP. Announced in Sept 2002, the first Polarization measurements of the CMB were taken by the DASI (Degree Angular Scale Interferometer) telescope. These observations have a direct view of the universe ~14 billion years ago (400,000 years after big bang). They map the seeds of the magnificent structures in the universe today, provide stringent tests of cosmological models for the origin of the universe, and determine the values of the cosmological parameters that describe our universe.
WMAP measured CMBR anisotropy over the full sky. Launched on June 30, 2001, WMAP is operating at the Earth-Sun Lagrange point, L2, where the earth, the sun, and the moon are nearly along a line and the instrument observes in the an area centered in the opposite direction. The first year results have shown the CMB power spectrum to be consistent with an accelerating universe with 73% of the energy density being in some form of dark energy and 23% in non-baryonic dark matter. WMAP also has found evidence for a late stage of reionization, which is presently under intense investigation.
Edward "Rocky" Kolb, Chairman