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Paper: Classification of Galaxies by Their Radial Profiles: Unbarred Early Types
Volume: 390, Pathways Through an Eclectic Universe
Page: 288
Authors: Aladro, R.; Gutiérrez, L.; Erwin, P.; Beckman, J.E.
Abstract: We classify 46 broad band surface-brightness profiles in the visible from a sample of nearby early-type unbarred galaxies imaged at the ING (La Palma) and in the SDSS. A key result is that the fraction of these galaxies showing truncations in their outer disks is relatively small (of order 10%). The largest single category of galaxies show what Erwin et al. (2005) have termed “Type III” profiles, which have an exponential inner disk, and also an exponential outer disk but with a shallower slope. They show no sign of truncations out to beyond at least five scale-lengths. The second most frequent category is that of Freeman’s (1970) “Type I” disks, which show a single exponential slope out to the radial limits of detection, with no sign of any truncation. Together, Types I and III account for over 75% of the galaxies in our sample. This is part of an ongoing program to use galaxy surface-brightness profiles to test models of galaxy formation.
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