NOAO >   Observing Info >   Approved Programs >   2003B-0335

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Proposal Information for 2003B-0335


PI: Andrew Connolly, University of Pittsburgh, ajc@phyast.pitt.edu
Address: Department of Physics and Astronomy, 3941 O'Hara Street, Pittsburgh, PA 15260, USA

CoI: Jeffery Gardner, University of Pittsburgh
CoI: Martha Haynes, Cornell University
CoI: Riccardo Giovanelli, Cornell University

Title: Calibration of the SDSS Spectroscopic Line Width Scaling Relations

Abstract: Understanding the angular momentum distribution of galaxies and its dependence on redshift, galaxy type and environment is fundamental to understanding the role that dynamics play in the formation and evolution of galaxies. Current studies of the distribution of angular momenta in galaxies (based on small, heterogeneous samples of galaxies) are found to be discrepant with the predictions of N-body simulations. We may, therefore, be reaching a stage where our models for the merging and evolution of the mass of galaxies and halos are not consistent with observational data. To address this issue we must obtain rotational velocities for large, homogeneous samples of galaxies. We propose here a series of observations that may enable just such a study. We request time to measure optical rotation curves for approximately 50 galaxies selected from the SDSS spectroscopic sample. These galaxies will be used to calibrate a linewidth vs rotational-velocity relation for the SDSS fiber spectroscopy. From existing work we expect that such a relation will hold for galaxies with z>0.05. Applying such a relation to the SDSS data we have the potential to measure the angular momentum of over 100,000 galaxies. This order of magnitude increase over current samples will enable the true distribution of angular momenta and its dependence on environment to be understood in great detail.


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