Query : 2004A&A...418..959T

2004A&A...418..959T - Astronomy and Astrophysics, volume 418, 959-978 (2004/5-2)

Are galactic disks dynamically influenced by dust?


Abstract (from CDS):

Dynamically cold components are well known to destabilize hotter, even much more massive components. E.g. stellar disks can become unstable by a small admixture of cold gas or proto-planetary disks might be destabilized by a small fraction of dust. In this paper we studied the dynamical influence of a cold dust component on the gaseous phase in the central regions of galactic disks. We performed two-dimensional hydrodynamical simulations for flat multi-component disks embedded in a combined static stellar and dark matter potential. The pressure-free dust component is coupled to the gas by a drag force depending on their velocity difference. It turned out that the most unstable regions are those with either a low or near to minimum Toomre parameter or with rigid rotation, i.e. the central area. In that regions the dust-free disks become most unstable for high azimuthal modes (m∼8), whereas in dusty disks all modes have a similar amplitude resulting in a patchy appearance. The structures in the dust have a larger contrast between arm and inter-arm regions than those of the gas. The dust peaks are frequently correlated with peaks of the gas distribution, but they do not necessarily coincide with them. Therefore, a large scatter in the dust-to-gas ratios is expected. The appearance of the dust is more cellular (i.e. sometimes connecting different spiral features), whereas the gas is organized in a multi-armed spiral structure. We found that an admixture of 2% dust (relative to the mass of the gas) destabilizes gaseous disks substantially, whereas dust-to-gas ratios below 1% have no influence on the evolution of the gaseous disk. For a high dust-to-gas ratio of 10% the instabilities reach a saturation level already after 30Myr. The stability of the gaseous disks also strongly depends on their Toomre parameter. But even in hot gaseous disks a destabilizing influence of the dust component has been found.

Abstract Copyright:

Journal keyword(s): galaxies: kinematics and dynamics - galaxies: spiral - interstellar medium: dust - ISM: structure - physical data and processes: instabilities

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NGC 4314 LIN 12 22 32.0223000912 +29 53 43.814812200 11.72 11.43 10.58     ~ 471 1
2 M 100 AGN 12 22 54.9299993592 +15 49 20.296257960 10.04 10.05 9.35     ~ 1780 2
3 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 4205 4
4 NGC 5248 GiG 13 37 32.0145074088 +08 53 06.496982448   11.4       ~ 486 0

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