Stellar kinematics in double-barred galaxies: the sigma-hollows
Abstract
We present SAURON integral-field stellar velocity and velocity dispersion maps for four double-barred early-type galaxies: NGC2859, NGC3941, NGC4725 and NGC5850. The presence of the inner bar does not produce major changes in the line-of-sight velocity, but it appears to have an important effect in the stellar velocity dispersion maps: we find two sigma-hollows of amplitudes between 10 and 40 km/s on either side of the center, at the ends of the inner bars. We have performed numerical simulations to explain these features. Ruling out other possibilities, we conclude that the sigma-hollows are an effect of the contrast between two kinematically different components: the high velocity dispersion of the bulge and the more ordered motion (low velocity dispersion) of the inner bar.
Keywords
Cite
@article{arxiv.0808.0517,
title = {Stellar kinematics in double-barred galaxies: the sigma-hollows},
author = {A. de Lorenzo-Cáceres and J. Falcón-Barroso and A. Vazdekis and I. Martínez-Valpuesta},
journal= {arXiv preprint arXiv:0808.0517},
year = {2009}
}
Comments
5 pages, 2 figures. Accepted for publication in ApJ Letters