AST-9529169 Grauer The purpose of this observationally-based research program is to measure the basic structural and color parameters of a representative sample of galaxies in the local part of the Universe. The research plan is designed to address a broad range of questions: How are structural scale lengths and measures such as the bulge-to-disk ratio related to a galaxy's Hubble type? Are these parameters significantly different for galaxies with active nuclei when they are compared to "normal" galaxies? What is a "normal" galaxy? How is the central surface brightness of a galaxy related to its Hubble type? What is the distribution of integrated magnitudes for galaxies of all types? What is the range of vertical scale heights for disk galaxies? What are the range of arm amplitudes in spiral galaxies? What can color gradients reveal concerning the age and chemical composition of stellar populations in and the dust content of galaxies? What fraction of spiral galaxies have nuclei which are not in the center of their disks? How are disk scale lengths related to the galactic environment, bulge size, and other parameters? To what extent does the spiral arm amplitude depend on the galactic environment and/or other structural parameters? The Steward Observatory 61-inch telescope, on Mt. Bigelow near Tucson, Arizona, will be used with a NICMOS3 256X256 pixel infrared photometric camera to obtain J(wavelength 1.25 micrometers) and K(wavelength 2.2 micrometers) band infrared images for a representative sample of 321 galaxies from the Uppsala General Catalogue (UGC). Collaborators will provide the corresponding optical images. This data base of structural and color information obtained over a wide range of wavelengths will be invaluable in modeling stellar populations, bulge-to-disk ratios, and surface brightness-distributions for galaxies of all types. The data should be crucial in understanding the effects of evolution in distant galaxies and will aid in understanding the morphologies of these galaxies. This information should also provide insights into active galaxies by providing the comparison objects required to determine if their global properties are as different from "normal" galaxies as are the nuclei of the galaxies. A sample data set consisting of 64 deep images of 44 galaxies has been obtained, reduced, and evaluated. The mean limiting isophotes at the 3 sigma confidence level are 20.4 magnitude per square arcsec at K band and 21.7 magnitude per square arcsec at J band in the infrared region of the spectrum. These data have been analyzed to produce radial profiles, bulge-to-disk ratios, central surface brightness, a vertical disk scale height, arm amplitudes for some nearly face-on spiral galaxies, and color gradients for 15 galaxies. When the project is completed, half of the deep images required for the entire survey of 321 galaxies will have been obtained and calibrated. In addition, the investigation of the astrophysical content of this data set will be well underway. This project will help to significantly improve research capabilities at an undergraduate institution. Students will be directly involved with science projects that are in progress. The involvement of the students in the research will substantially improve the educational experience for students at a primarily undergraduate institution by serving as the impetus for importing new ideas and forefront technology to the undergraduate students.
