NOAO >   Observing Info >   Approved Programs >   2001B-0334

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Proposal Information for 2001B-0334


PI: Rob Swaters, Carnegie Institution of Washington, swaters@dtm.ciw.edu
Address: 5241 Broad Branch Road NW, Washington, DC 20015, USA

CoI: Matthew Bershady, University of Wisconsin
CoI: David Andersen, Penn State University

Title: The Central Mass Distribution of Low Surface Brightness Galaxies

Abstract: The inner slopes of the mass distributions of low surface brightness galaxies (LSBGs) are poorly constrained observationally. Recent studies find conflicting results, some concluding that the inner slopes of the mass distributions in LSBGs are steep, others that they are shallow. It is critical to resolve this controversy, as the inner slopes of LSBGs provide a key means to constrain theories of galaxy formation and the nature of dark matter. The controversy may well be the result of a combination of uncertainties due to slit alignment errors, which are particularly acute for LSBGs, and non-circular motions, both of which may lead to an underestimate of the inner slope. To break the existing controversy we propose to use DensePak on WIYN to obtain high- resolution, two-dimensional velocity fields of LSBGs. The proposed observations eliminate the major uncertainties of long-slit observations: galaxy centers can be determined directly from the proposed observations, and non-circular motions can be mapped and modeled. This makes an accurate measurement of the inner slope possible. We will confront our measured slopes with predictions made by theories of galaxy formation, which in turn will shed light on the nature of dark matter. In addition, we will use these observations to measure the intrinsic disk ellipticity.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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