A Morphological Study of Sigma-Drop Galaxies

Comerón, S.; Knapen, J. H.; Beckman, J. E.
Referencia bibliográfica

Highlights of Spanish Astrophysics V, Astrophysics and Space Science Proceedings. ISBN 978-3-642-11249-2. Springer-Verlag Berlin Heidelberg, 2010, p. 271

Fecha de publicación:
2010
Número de autores
3
Número de autores del IAC
3
Número de citas
0
Número de citas referidas
0
Descripción
We study a sample of 20 galaxies with an observed central drop in the stellar velocity dispersion (σ-drop) matched with a control sample of galaxies without a σ-drop. We search for correlations between σ-drops and the properties, primarily morphological, of the inner zones and discs of their host galaxies. Both morphological parameters and luminosity profiles are used to classify the samples. We find a larger fraction of Hα rings and nuclear dust spirals in the σ-drop sample. We also find that the fraction of Seyfert galaxies in the σ-drop sample is bigger than that of LINERs and that the reverse is true for the control sample. Our findings indicate that a σ-drop is very probably due to inflow-induced star formation in a dynamically cool disc, or in a gas ring, shock focused by an inner Lindblad resonance above a certain critical density level. The same mechanism that feeds the nuclear ring or the nuclear disc may well be responsible for the higher rate of Seyfert galaxies among the σ-drop hosts.