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Session 64 - New Digital Surveys in the Optical and Near IR: Technical Challenges and Scientific Opportunities - II.
Topical, Oral session, Wednesday, June 10
We discuss the current status of a three-color survey of fields of the digitized Second Palomar Observatory Sky Survey (DPOSS). Eventually, the DPOSS catalogs will be released to the astronomical community. The final catalog will contain an estimated minimum of 50,000,000 (50 million) galaxies, and over 2,000,000,000 (2 billion) stars, down to the equivalent blue limiting magnitude of 22., and with star-galaxy classifications accurate to 90magnitude of 21. An important addition is a program to collect extensive CCD calibration data in the Gunn gri system with the Palomar 60". This represents a considerable advance over other, currently existing optical sky surveys based on large-format photographic plates. A great variety of scientific projects should become possible using this major data set, including the following: studies of galaxy clustering and of the large-scale structure in the low-redshift universe, as tests of structure formation models; galaxy counts at moderate depth, as a function of magnitudes, colors, and morphology, to be used in tests of galaxy evolution over the past few Gigayears; a search for high redshift (z > 4) quasars, and active galactic nuclei at lower redshifts; mass optical identifications of radio, IR, and x-ray sources; generation of objectively defined catalogs of clusters and groups of galaxies; a search for previously unknown sparse globular clusters and dwarf spheroidal galaxies; cataloging of low surface brightness galaxies; a search for objects with peculiar colors or variability; and many others. In particular, we review efforts to perform automatic galaxy classification using artificial neural network image classifiers. This powerful technique is used to map a multivariate photometric parameter space to the revised Hubble system of galaxy classification. We present a new morphological classification approach using Fourier image models to identify barred and ringed spiral systems.
Program listing for Wednesday