http://arxiv.org/abs/1405.5836
The standard disc formation scenario postulates that disc form as the gas cools and flows into the centre of the dark matter halo, conserving the specific angular momentum. Major mergers have been shown to be able to destroy or highly perturbed the disc components. More recently, the alignment of the material that is accreted to form the galaxy has been pointed out as a key ingredient to determine galaxy morphology. However, in a hierarchical scenario galaxy formation is a complex process which combines these processes, and others, in a non-linear way so that the origin of galaxy morphology remains to be fully understood. We aim at exploring the differences in the formation histories of galaxies with a variety of morphology but quite recent merger histories to identify which mechanisms are playing a major role. We will analyse when minor mergers could be considered relevant to determine galaxy morphology. We also study the specific angular momentum content of the disc and central spheroidal components, separately. We use cosmological hydrodynamical simulations that include an effective, physically-motivated Supernova feedback which is able to regulate the star formation in haloes of different masses. We analysed the morphology and formation history of a sample of 15 galaxies of a cosmological simulation. We performed a spheroid-disc decomposition of the selected galaxies and their progenitor systems. The angular momentum orientation of the merging systems as well as their relative masses are estimated to analyse the role played by orientation and by minor mergers in the determination of the morphology. We found the discs to be formed by conserving the specific angular momentum in accordance with the classical disc formation model. The specific angular momentum of the stellar central spheroid correlates with the dark matter halo angular momentum determining a power law. Abridged
S. Pedrosa, P. Tissera and M. Rossi
Fri, 23 May 14
35/44
Comments: 10 pages, 9 figures, accepted for publication in A&A
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