AAS 201st Meeting, January, 2003
Session 65. Stars and Galactic Structure in the Sloan Digital Sky Survey
Special, Tuesday, January 7, 2003, 2:00-3:30pm, 6AB

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[65.05] The Scale Height of the Thick Disk

C. M. Rockosi (University of Washington)

The Sloan Digital Sky Survey is in the process of creating a catalog of homogeneous, uniformly-calibrated optical photometry in multiple bandpasses over a large area of the sky. The combination of these properties make the SDSS data an effective tool for investigating the basic structural parameters of the Galaxy on large scales. One such aspect of Galactic structure which is of direct interest to theories of external galaxy formation is the shape of the Galactic thick disk component. The age, metal abundance and dynamical properties of the thick disk indicate that it is intermediate between the older, more metal-poor halo and younger thin disk, suggesting that the thick disk represents a particular phase in the evolution of our Galaxy. Theories of the formation of the Galaxy predict different structural parameters for the thick disk depending on the relative importance of merging and dissipational collapse. The importance of mergers in galaxy evolution is a current issue in structure formation theory, making the shape of the thick disk of our own Galaxy an important cosmological constraint. I will discuss what the large-area SDSS photometry can contribute to our knowledge of the thick disk, and compare its measured properties with predictions made by several theories of its formation.

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