A minor-merger origin for inner disks and rings in early-type galaxies

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Eliche Moral, María del Carmen
González García, A. C.
Balcells, M.
Aguerri, J. A. L.
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Amer. Inst. Physics
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Nuclear disks and rings are frequent galaxy substructures, for a wide range of morphological types [from S0 to Sc, see e.g., 6, 8]. We have investigated the possible minor-merger origin of inner disks and rings in spiral galaxies through collisionless N-body simulations. The models confirm that minor mergers can drive the formation of thin, kinematically-cold structures in the center of galaxies out of satellite material, without requiring the previous formation of a bar. Satellite core particles tend to be deposited in circular orbits in the central potential, due to the strong circularization experienced by the satellite orbit through dynamical friction. The material of the satellite core reaches the remnant center if satellites are dense or massive, building up a thin inner disk; whereas it is fully disrupted before reaching the center in the case of low-mass satellites, creating an inner ring instead.
© 2010 AIP Publishing LLC. International Conference on Hunting for the Dark: the hidden side of galaxy formation (2009. Qawra/Malta). Supported by the Spanish Programa Nacional de Astronomía y Astrofísica (project AYA2006-02358), by the Madrid Regional Government through the ASTRID Project (S0505/ESP-0361) for development and exploitation of astronomical instrumentation (, and by the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: "First Science with the GTC" (
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