The True Shapes of Elliptical Galaxies

Ohio University, Athens OH

Investigators

Abstract

AST-0407152 Statler The problem of determining the intrinsic shape distribution of elliptical galaxies is an 80-year-old unsolved problem of classical astronomy, as well as a crucial issue for theories of galaxy formation and evolution. Recent developments in modeling and instrumentation mean that a solution is now possible. Maps of the stellar velocity fields of 25 elliptical galaxies observed with a powerful new spectrograph will be modeled by an approach developed by the principal investigator. Firstly, by enabling the measurement of the velocity field at all points of a galaxy simultaneously, the new SAURON spectrograph operating on the 4.2m William Herschel telescope can finally produce data of the quality and coverage needed by the modeling. Secondly, a new approach developed by the principal investigator enables these data to be modeled in a reasonable amount of time with current computational capacity. This technique, the only practical method for constraining intrinsic shapes, has already been applied successfully to two of the full sample of 25 elliptical galaxies. Modeling the rest, and comparing the numerical technique to new analytical solutions, will enable a proper estimate of the distribution of intrinsic shapes. The project sets up a new international collaboration with a leading multi-institution European team (Sterrewacht Leiden, Obs.de Lyon, Oxford University). The principal investigator and his team will spread scientific and astronomical understanding amongst a traditionally under-served community, by virtue of Ohio University's location in the Appalachian foothills and the use of a monthly popular radio program.