CAREER The Digital Sky: Bringing Cosmology into the Classroom

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

AST-9984924 CONNOLLY It is becoming increasingly apparent that the next decade will mark the beginning of a golden age for observational cosmology. Technological advances have now made it feasible to map the properties and distributions of galaxies in the local and distant Universe with unprecedented detail. New astronomical surveys are underway, or nearing completion, that will produce images and spectroscopy for hundreds of millions of objects each with measurements covering the full electromagnetic spectrum (from X-ray wavelengths through to radio frequencies). In the near future we will no longer be restricted to applying for telescope time at national or private facilities. Instead, people will be able to "dial-up" a region of the sky (a virtual observatory is becoming a reality). This new paradigm for undertaking research will have profound implications for research at the undergraduate, graduate and postdoctoral levels. One of the fundamental questions to be addressed with these new multi-frequency surveys is how do galaxies evolve as a function of redshift or lookback time. Extant photometric and spectroscopic surveys provide a framework for this evolution, finding a rapid increase in the total star formation rate from a redshift of z = 0 to redshift z = 1 (a factor of 10 increase in luminosity). The limitation of these surveys is that they extend over very small regions of the sky (for instance the deepest image ever undertaken, the Hubble Deep Field, subtends only 2 arcminutes on a side) and comprise only a few hundred galaxies. Consequently, we do not have the numbers of galaxies to identify anything more than the broad features of galaxy evolution (i.e. our analyses are shot noise limited) nor do we survey sufficient volume to be able to say whether we are seeing a true reflection of how the Universe evolves (i.e. we are sample variance limited). Many of these issues will be resolved by the new multicolor sky surveys. The Sloan Digital Sky Survey alone will contain > 108 galaxies and cover a huge volume of the sky. For the first time, there will be access to large, statistically complete samples of galaxies that can provide an accurate census of the local and distant Universe. Through the use of novel statistical techniques we can use the multicolor information within these surveys to estimate the physical properties of galaxies (i.e. their redshifts, spectral types and luminosities). From this we can then directly trace how galaxies change as a function of redshift, galaxy type and environment and thereby guide the theories of galaxy formation and evolution. Beyond the insights into the physics of galaxy formation and evolution, these data will open new avenues for introducing students into the astrophysical sciences. These multifrequency surveys can be combined to form a digital sky; a database of stars and galaxies covering a large fraction of the night sky that is accessible to undergraduate and graduate students alike. Students will, in essence, have access to their own telescope and can explore or analyze the data at their own pace. Given the enormous research and teaching potential of these new sky surveys, a program of research and education designed to build the graduate and undergraduate astrophysics programs at the University of Pittsburgh will be carried out. The principle goals of these programs are: o To quantify how the properties of galaxies (their spectral types, star formation and luminosities) evolve from a redshift of z = 0 to z = I and to determine what physical processes drive these changes. o To trace the clustering of galaxies at low and intermediate redshifts (z < 1) as a function of lookback time, galaxy type and environment and to relate these observations to current cosmological theories of galaxy formation and evolution. o To develop the new virtual observatories into an undergraduate and graduate research and teaching environment (a "virtual telescope"). One that enables students to undertake exploration of online astrophysical databases at their own pace. o To integrate computational sciences into astrophysics to enable a cross-fertilization of ideas and tech-niques at the graduate and undergraduate level. This project is funded by the Division of Astronomical Sciences. ***