NOAO >   Observing Info >   Approved Programs >   2004A-0135

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Proposal Information for 2004A-0135


PI: Rob Swaters, Johns Hopkins University / STScI, swaters@pha.jhu.edu
Address: Physics Department, 3400 N. Charles St, Baltimore, MD 21218, USA

CoI: David Andersen, MPIA Heidelberg
CoI: Matthew Bershady, University of Wisconsin
CoI: Marc Verheijen, University of Potsdam
CoI: Kyle Westfall, University of Wisconsin

Title: Broad Band Imaging of Disk Galaxies with H(alpha) Velocity Fields

Abstract: We are carrying out a large project to measure the kinematic structure and the masses of galactic disks. To this end, we are in the process of obtaining H(alpha) velocity fields for a sample of 100 spiral galaxies, and stellar absorption line kinematics for a subsample of 40 of these. We propose to use the 2.1m to obtain UBVRI imaging for these 100 galaxies. The proposed observations serve two main purposes. \bf 1) We will compare morphological structures and asymmetries to those in the H(alpha) kinematics to discriminate between recent accretion and asymmetric halos as the dominant cause of disk asymmetries. \bf 2) We will calibrate the stellar mass-to-light ratios (M/Ls) derived from population synthesis models. Because of uncertainties in the stellar initial mass function, these models only provide \it relative M/Ls. We will compare these to the M/Ls we will derive from the absorption line kinematics to provide an \it absolute calibration. In addition, we will use the proposed observations to derive the radial light distributions needed for fitting mass models to the rotation curves, and to study the coupling between the light distribution and the rotation curve shape. \bigskip\bf Note: This proposal was granted 7 nights for 2003B to observe the first half of the sample. Here we ask for time to complete this project.


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NOAO >   Observing Info >   Approved Programs >   2004A-0135

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