Research Programs & Facilities

From the mountains of Chile to the glaciers of the South Pole, Ohio State astronomy faculty travel the world as they work at the cutting edge of astronomical research. The research themes and interests of the faculty overlap considerably, providing an opportunity for students and postdocs to work closely with a variety of experts in many areas. The main research programs of the department may be summarized as follows:

Extrasolar Planetary Systems
	Observational searches for extrasolar planets using gravitational microlensing, and cluster and field star transit surveys. Observational and theoretical studies of the demographics of planetary systems, and the possible linkages with the systematic properties like age and metallicity of the host stars of planetary systems. Follow-up studies of transiting planet systems, and surveys for new extra-solar planets as part of the SDSS-III Collaboration.
Stellar Evolution
	Theoretical and observational studies of the structure and evolution of stars, with applications that include helioseismology, the solar neutrino problem, the influence of stellar nucleosynthesis on chemical abundances, the properties of star clusters, and the measurement of fundamental stellar properties (mass, radius, rotation and activity, etc.)
Star Formation & Interstellar Chemistry
	Theoretical, observational, and experimental studies of molecules and dust grains in interstellar and circumstellar environments, with attention to formation processes and diagnostics of physical conditions. Includes observational and theoretical investigations of interstellar gas and dust in the Milky Way and other galaxies, and the use of optical, and especially infrared observations to probe star formation activity.
Galactic Structure
	Observational investigations of the stellar contents, chemical abundances, and dynamics of the Galactic Center. Observational studies of the stelar populations of the bulge, disk, and halo of the Milky Way, and interpretation of observational data in light of dynamical models. Analysis of Galactic structure using SDSS-II and SDSS-III data.
Gravitational Lensing and Microlensing
	Theoretical and observational studies of gravitational lensing from scales ranging from microlensing due to stars to strong lensing due to clusters of galaxies, with applications for determining the nature of dark matter, measuring limb darkening in stellar atmospheres, probing the structures of quasars and dark-matter halos, and searching for extra-solar planets.
Galaxy Formation & Evolution
	Observational studies of the structure and stellar content of external galaxies, from the Local Group to young galaxies at cosmological distances. Modeling of the dynamics and shapes of different types of galaxies. Theoretical investigations of galaxy formation and galaxy transformations (e.g., via major or minor mergers), using analytic methods and numerical simulations on supercomputers.
Active Galactic Nuclei & Quasars
	Time-series analysis of multiwavelength monitoring campaigns, to constrain the sizes, structures, and central black hole masses of AGNs and Quasars, investigations of the causes of AGN activity and the physical state of active nuclei using optical, infrared, ultraviolet, and X-ray imaging and spectroscopy. Surveys for high-redshift quasars and the evolution of the cosmic quasar population, and observational studies of accretion and outflow phenomena in active galaxies. Work on AGNs is carried out using ground-based telescopes, the Hubble Space Telescope, and various orbiting observatories including the Chandra and XMM/Newton X-ray observatory.
Cosmology & Large-Scale Structure
	Observational studies of the cosmic distance scale and the high-redshift universe. Theoretical studies of Big Bang nucleosynthesis, the cosmic microwave background, large-scale structure, and the intergalactic medium, with goals that include testing the standard models of particle physics and cosmology, determining the baryon content of the universe and other fundamental cosmological parameters, and providing a theoretical framework for interpreting the observed evolution and clustering of galaxies, quasars, and quasar absorption-line systems at UV, visible, and X-ray wavelengths. Analysis of large-scale structure and galaxy and quasar properites in the Sloan Digital Sky Survey (SDSS-II and SDSS-III).
Astronomical Instrumentation
	Designing and building advances, state-of-the-art optical and infrared instruments for small and large telescopes (1-meter to 8.4-meter) that enable front-line astronomical research. Design and deployment of instrument control and detector systems, large-mirror aluminization systems, and software for astronomical data analysis. OSU has deployed nearly a dozen instruments at obseratories on 6 continents (North America, South America, South Africa, Australia, Europe, and Asia Minor).
Nuclear & Particle Astrophysics
	Theoretical and experimental investigations of astrophysically important nuclear and particle processes, with applications that include stellar and Big Bang nucleosynthesis, solar neutrinos, interactions of cosmic rays with the cosmic background radiation, the nature of particle dark matter, and the emission and detecton of neutrinos from supernovae.
Atomic Astrophysics
	Theoretical studies of atomic physics and spectral-line formation in astrophysical environments such as gaseous nebulae, stellar atmospheres and interiors, supernovae, and active galactic nuclei. Work at OSU is focussed on the precise calculation of atomic parameters using large-scale quantum mechanical calculations carried out at the Ohio Supercomputing Center. Prof. Anil Pradhan and his group are members of the international IRON project to compute fundamental atomic parameters (excitation, photoionization, and recombination) for all iron-peak elements.

Observing Facilities

MDM Observatory

OSU has a one-quarter share of the MDM Observatory, in partnership with Dartmouth College, Columbia University, and the University of Michigan. MDM operates a 2.4-meter and 1.3-meter telescopes on the southwest ridge of Kitt Peak near Tucson Arizona. The 2.4-meter Hiltner telescope is one of the best in its class anywhere, routinely delivering sub-arcsecond imaging. Equipped with modern optical and infrared imagers and spectrometers, MDM is the primary small-project and student training telescope used by OSU astronomers.

In an age of giant 8- and 10-meter diameter telescopes, the smaller MDM telescopes are ideal for observations of brighter nearby stars and galaxies, and for following up the discovery of X-ray sources by space observatories like Chandra or XMM/Newton. They are also excellent for undertaking long-term studies of variable stars, active galaxies, and searches for planetary transits (planets around distant stars that briefly partically eclipse their parent stars). We are continuing to develop new instrumentation and new observing strategies to keep these smaller telescopes at the forefront of astronomical research.

Large Binocular Telescope

Ohio State is a one-eight partner in the Large Binocular Telescope (LBT) project to build a twin 8.4-meter mirror telescope on Mt. Graham in Southern Arizona. With an additional grant from the Research Corporation, we will have one-sixth of the observing time on the LBT available for faculty and student research projects. LBT saw first light in October 2005, and entered its one- and two-mirror commissioning phases in 2007. Full operations are expected to begin in late 2008. OSU has built the large-mirror aluminization system for the twin 8.4-meter mirrors, a fixed-secondary mirror system, and is currently assembling a pair of advanced Multi-Object Double Spectrographs (MODS), the first-light facility optical spectrometers for the LBT.

The LBT, with its twin 8.4-meter diameter prime mirrors, will be the largest optical/IR telescope on a single mount yet constructed. With nearly 24 times the light gathering power of the Hubble Space Telescope, LBT will be able to obtain spectra of objects Hubble can only image. These spectra will provide the essential information for determining distances, evolutionary state, and chemical composition of the most distant galaxies known in the universe. With the MODS spectrograph being built by OSU, LBT astronomers will be able to study objects that were formed when the universe was less than 10% of its present age, and to see how they have evolved ino the galaxies and stars that we see today in nearby space.

The other partners in the LBT project are the University of Arizona, an Italian consortium (INAF) led by the Arcetri Observatory in Florence, a German consortium (LBTB) headed by the Max-Planck-Institute for Astrophysics in Heidelberg, and the Research Corporation of Tucson, which has awarded parts of its one-eight share to OSU, Notre Dame, Virginia, and Minnesota.

SMARTS

OSU is a founding member of the SMARTS Consortium, which operates the small and medium aperture research telescopes at the Cerro Tololo Interamerican Observatory in Chile. Specifically, we have provided the ANDICAM dual optical/IR imager for the CTIO 1.3-meter telescope, and built the Y4KCam 4Kx4K CCD imager for the CTIO 1.0-meter telescope.

Sloan Digital Sky Survey

OSU is a partner in the Sloan Digital Sky Survey. We are particularly involved in the follow-up of supernova candidates observed as part of the Sloan Supernova Survey, the study of the content and structure of the Milky Way through the 250,000 stellar spectra from the SEGUE project, and the extraction of cosmological and galaxy formation parameters from the previous SDSS-I and SDSS-II databases.

We are an institutional member of the new SDSS-III Collaboration, with scientists active in the large-scale structure, Galactic structure, and extra-solar planet surveys of SDSS-III.