Published in
Oxford University Press (OUP), Monthly Notices of the Royal Astronomical Society, 2(369), p. 853-859
DOI: 10.1111/j.1365-2966.2006.10359.x
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- [arxiv.org] | PDF
- [www.researchgate.net]
- [arxiv.org] | PDF
- [citeseerx.ist.psu.edu] | PDF
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Lifetime of nuclear velocity dispersion drops in barred galaxies
,
Nicolas Champavert
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Abstract
We have made hydro/N-body simulations with and without star formation to shed some light on the conditions under which a central kinematically cold stellar component (characterized by a velocity dispersion drop or σ-drop) could be created in a hot medium (e.g. a bulge) and survive enough time to be observed. We found that the timescale for a σ-drop formation could be short (less than 500 Myr) whereas its lifetime could be long (more than 1 Gyr) provided that the central region is continuously or regularly fed by fresh gas which leads to a continuous star formation activity. Star formation in the central region, even at a low rate as 1M_{sol} yr^{-1}, is mandatory to sustain a permanent σ-drop by replacing heated particles by new low-σ ones. We moreover show that as soon as star formation is switched off, the σ-drop begins to disappear.