NOAO >   Observing Info >   Approved Programs >   2002B-0372

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Proposal Information for 2002B-0372


PI: Sheila Kannappan, University of Texas at Austin, sheila@astro.as.utexas.edu
Address: 2511 Speedway, RLM 15.308 C1400, Austin, TX 78712, USA

CoI: Matthew Bershady, University of Wisconsin at Madison
CoI: Elizabeth Barton Gillespie, University of Arizona

Title: Kinematic Tully-Fisher Offsets at z=0 and Beyond

Abstract: Interpreting apparent evolution in the Tully-Fisher (TF) relation relies on knowing whether shifts in slope and zero point reflect changes primarily in luminosity or primarily in velocity width. For example, kinematic offsets that mimic luminosity evolution may arise when emission-line data fail to sample outer disk velocities. However, this effect cannot fully explain the discrepancies between different intermediate-z TF studies. Therefore we propose to quantify kinematic offsets from two other sources: (a) kinematic distortions and (b) systematic errors in inclination or position angle. Using 2D H(alpha) velocity fields for a sample of known low-z TF outliers and a control sample, we will model distortions and determine kinematic inclinations and position angles. We can then compare the new 2D and original 1D velocity widths to determine kinematic contributions to TF offsets. To apply our results to higher z, we will degrade the images and spectroscopy, using the 2D H(alpha) fields to model slit aperture effects. Both the raw and degraded data will be used to search for ways to estimate kinematic offsets based on galaxy properties in the absence of 2D velocity fields.


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 >   2002B-0372

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