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The Metamorphosis ofTidally Stirred DwarfGalaxies Lucio MayerFabio GovernatoMonica Colpi2001 год

The Metamorphosis of Tidally Stirred Dwarf Galaxies
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Аннотация: We present results from high-resolution N-Body/SPH simulations of rotationally supported dwarf irregular galaxies moving on bound orbits in the massive dark matter halo of the Milky Way.The dwarf models span a range in disk surface density and the masses and sizes of their dark halos are consistent with the predictions of cold dark matter cosmogonies. We show that the strong tidal field of the Milky Way determines severe mass loss in their halos and disks and induces bar and bending instabilities that transform low surface brightness dwarfs (LSBs) into dwarf spheroidals (dSphs) and high surface brightness dwarfs (HSBs) into dwarf ellipticals (dEs) in less than 10 Gyr. The final central velocity dispersions of the remnants are in the range 8-30 km/s and their final $v/\sigma$ falls to values $< 0.5$, matching well the kinematics of early-type dwarfs. The transformation requires the orbital time of the dwarf to be $\simlt 3-4$ Gyr, which implies a halo as massive and extended as predicted by hierarchical models of galaxy formation to explain the origin of even the farthest dSph satellites of the Milky Way, Leo I and Leo II. Only dwarfs with central dark matter densities as high as those of Draco and Ursa Minor can survive for 10 Gyr in the proximity of the Milky Way: this is naturally achieved within hierarchical models, where the densest objects should have small orbital times due to their early formation epochs. Part of the gas is stripped and part is funneled to the center due to the bar, generating one strong burst of star formation in HSBs and smaller, multiple bursts in LSBs. Extended low-surface brightness stellar and gaseous streams originate from LSBs and, when projected along the line of sight, can lead to overestimate the mass-to-light ratio of the bound remnant by a factor $\simlt 2$,
Год издания: 2001
Авторы: Lucio Mayer, Fabio Governato, Monica Colpi, Ben Moore, Thomas Quinn, James Wadsley, Joachim Stadel, George Lake
Издательство: IOP Publishing
Источник: The Astrophysical Journal
Ключевые слова: Galaxies: Formation, Evolution, Phenomena, Stellar, planetary, and galactic studies, Astronomy and Astrophysical Research
Другие ссылки: The Astrophysical Journal (PDF)
The Astrophysical Journal (HTML)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (HTML)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (PDF)
arXiv (Cornell University) (HTML)
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