NOAO >   Observing Info >   Approved Programs >   2007B-0170

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Proposal Information for 2007B-0170


PI: Vera Rubin, Carnegie Institution of Washington, rubin@dtm.ciw.edu
Address: Department of Terrestrial Magnetism, 5241 Broad Branch Rd, NW, Washington, DC 20015, USA

CoI: Deidre Hunter, Lowell Observatory

Title: A Search for H(alpha) Emission in the Far Outer Discs of Extremely Large Spiral Galaxies

Abstract: Little is known about the kinematics of galaxies far beyond the relatively bright regions sampled in radio or optical radial velocity studies. Most often, the velocities are obtained as part of large surveys, where the effort is made to obtain many rotation curves, rather than to extend a rotation curve as far as possible. Because the composition of dark matter remains unknown, it is important to devise observations that will help to constrain its properties. We propose to obtain ultra-deep \ha images (in the rest frame of the galaxy) for UGC 2885 and NGC 801, two extremely large Sc galaxies. We expect to detect \ha regions far beyond their nuclei and into the extreme outer disc, for which we will then obtain radial velocities. Increased knowledge concerning the kinematics of these galaxies will tighten the constraints on mass models, and shed light on the properties of dark matter. Ultimately, we hope to learn more about the outermost galaxy, where disc and halo blend.


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



NOAO >   Observing Info >   Approved Programs >   2007B-0170

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