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arXiv · 0808.0517

Stellar kinematics in double-barred galaxies: the sigma-hollows

A. de Lorenzo-Cáceres·J. Falcón-Barroso·A. Vazdekis·I. Martínez-Valpuesta
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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.

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A. de Lorenzo-Cáceres, J. Falcón-Barroso, A. Vazdekis, I. Martínez-Valpuesta. 2008-08-04. Stellar kinematics in double-barred galaxies: the sigma-hollows. https://doi.org/10.1086/592145

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