NOAO >   Observing Info >   Approved Programs >   2002A-0227

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Proposal Information for 2002A-0227


PI: Elisabeth B. Ambrose, University of Texas at Austin, eba@astro.as.utexas.edu
Address: C1400, Austin, TX 78712, USA

CoI: John Kormendy, University of Texas at Austin
CoI: Sheila J. Kannappan

Title: Pseudobulges in Disk Galaxies: The Initial Sample

Abstract: The most fundamental morphological division of galaxies is into elliptical galaxies and disks. Elliptical galaxies consist mainly of old stars and are ellipsoidal in shape, while disk galaxies consist of a disk component that continually makes stars. Many disk galaxies also contain a ``bulge" that is similar to a small elliptical galaxy and that, it is thought, was formed when the galaxy formed. However, recent work suggests that not all bulges of disk galaxies are, in fact, like tiny ellipticals. Rather, some bulges have characteristics associated with disks and are now thought to have been built out of the disk after the galaxy formed. These are called pseudobulges. Pseudobulges are known to exist, and enough of their characteristics are known to be able to identify the prototypical examples. However, no rigorous study of their properties has been performed to date. This means that we do not yet have a rigorous prescription for identifying pseudobulges, and we do not have a quantitative understanding of how often, as a function of Hubble type, the apparent bulges of disk galaxies are really pseudobulges. We propose to use the 2.1 m telescope to get imaging and kinematic data on a sample of disk galaxies known to contain prototypical pseudobulges and classical bulges. This sample is a subset of a larger sample of disk galaxies for which similar data will be taken in the future. The data are needed in order to determine a reliable prescription for identifying pseudobulges in disk galaxies.


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