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arXiv · 2303.05586

Gravitational Instability of Gas-Dust Circumnuclear Disks in Galaxies

Roman Tkachenko·Vladimir Korchagin·Boris Jmailov
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Abstract

We numerically study the origin of the multi-armed spiral structure observed in the circumnuclear gaseous mini-disks of nearby galaxies. We show that the presence of dust in such disks and its interaction with the gravitationally stable gaseous component leads to the development of a multi-armed spiral structure. As a particular example, we study the formation of the multi-armed spiral pattern in the mini-disk of the galaxy NGC 4736, for which the observational data for the rotation and the density distribution are available. We find that the multi-armed spiral structure grows in the stable gaseous mini-disk of NGC 4736 if the gas-to-dust ratio is about 5-20 percent. We also demonstrate that together with the dust concentration, the important factor for the development of instability is the size of the dust grains. A nonlinear multi-armed spiral pattern develops in the stable gaseous disk with sizes of grains larger than one micron. If future observations confirm the presence of a large amount of dust in the mini-disks of galaxies, this will pinpoint the mechanism of the formation of the multi-armed spiral structure in them.

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Roman Tkachenko, Vladimir Korchagin, Boris Jmailov. 2023-03-09. Gravitational Instability of Gas-Dust Circumnuclear Disks in Galaxies. https://doi.org/10.3390/galaxies11020041

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