NOAO > Observing Info > Approved Programs > 2002A-0315
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NOAO > Observing Info > Approved Programs > 2002A-0315 |
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PI: Stephane Courteau, Univ. of British Columbia, courteau@astro.ubc.ca
Address: 6224 Agricultural Rd., Vancouver, BC V6T 1Z1, Canada
CoI: Matthew Bershady, Univ. of Wisconsin
CoI: Hans-Walter Rix, MPIA, Heidelberg
CoI: David Andersen, MPIA, Heidelberg
Title: A Critical Test of Structure Formation Models
Abstract:
We seek to constrain current models of structure formation and the
hypothesis of maximal disks in luminous spiral galaxies. Structure
formation models based on most CDM cosmologies favor dark galactic halos
that dominate the potential even in the inner parts of galaxies.
Opposite conclusions are reached if the rotation curve of galaxies can
only be modeled with the highest (maximal) disk mass-to-light ratio.
Stellar population and Tully-Fisher (TF) analyses of low and high
surface brightness galaxies suggest a picture where dark matter
concentration correlates with surface brightness. Since bright barred
galaxies have typically higher surface brightness than their un-barred
cousins, they should have different halo concentrations and thus should
define their own separate TF sequence. This clear prediction cannot be
tested at present since barred galaxies have systematically been excised
from TF samples in the past. We propose to augment our own TF Shellflow
sample with 24 barred galaxies to test this claim. Whether barred
galaxies define a brighter TF sequence or they behave dynamically as un-
barred galaxies, in a TF sense, is of utmost importance for structure
formation models. Fiber spectroscopy with WIYN/SparsePak is required to
model the full 2D velocity fields of the bulge, bar, and disk
components. Disk scale lengths, magnitudes, and colors are measured
from 0.9m deep V-I photometry.
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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NOAO > Observing Info > Approved Programs > 2002A-0315 |
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