NOAO >   Observing Info >   Approved Programs >   2003A-0042

Small NOAO Logo

Proposal Information for 2003A-0042


PI: Deidre Hunter, Lowell Observatory, dah@lowell.edu
Address: 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA

CoI: Vera C. Rubin, Carnegie Institution of Washington--DTM
CoI: Linda S. Sparke, Univ. of Wisconsin
CoI: Rob A. Swaters, Johns Hopkins Univ.
CoI: Stephen Levine, US Naval Observatory

Title: The Stellar Velocity Dispersion in Irregular Galaxies: NGC 4449

Abstract: We do not understand the fundamental physical shape of the most common galaxies in the universe, dwarf irregulars. Some have suggested that irregulars are thick disks while others have suggested that they are triaxial in shape. The stellar velocity dispersion, coupled with rotational information, is a diagnostic of how kinematically hot a system is, and, therefore, is an indicator of its structure. The stellar velocity dispersion has been measured in only two irregular galaxies so far and the ratio V/\sigma_stars contradicts the results of studies of apparent minor-to-major axis ratios. We are requesting telescope time to measure the stellar velocity dispersion in the irregular galaxy NGC 4449 for which we have observations of the rotation of the stars and gas. Coupled with our model of the stellar and gas rotational dynamics, the stellar velocity dispersion measurements will allow us to constrain the physical structure of the stellar disk of NGC 4449.


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 >   2003A-0042

noaoprop-help@noao.edu

Small NOAO Logo