Classification of Galaxies by Their Radial Profiles: Unbarred Early Types

Aladro, R.; Gutiérrez, L.; Erwin, P.; Beckman, J. E.
Bibliographical reference

Pathways Through an Eclectic Universe ASP Conference Series, Vol. 390, proceedings of the conference held 23-27 April, 2007 at Santiago del Teide, Tenerife, Spain. Edited by J. H. Knapen, T. J. Mahoney, and A. Vazdekis San Francisco: Astronomical Society of the Pacific, 2008., p.288

Advertised on:
6
2008
Number of authors
4
IAC number of authors
0
Citations
0
Refereed citations
0
Description
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 tet{erwin05} 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 tet{free70} ``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.