The Milky Way and Andromeda galaxies in a constrained hydrodynamical simulation: morphological evolution
EntityUAM. Departamento de Física Teórica
10.1051/0004-6361/201425494Astronomy and Astrophysics 577 (2015): A3
ISSN0004-6361 (print); 1432-0746 (online)
Funded byC.S. and P.C. acknowledge support from the Leibniz Gemeinschaft through grant SAW-2012-AIP-5 129. C.S. acknowledges support from the HPC-EUROPA2 project, with the support of the European Community – Research Infrastructure Action of the FP7. S.E.N. acknowledges support from the Deutsche Forschungsgemeinschaft under the grants MU 1020 16-1 and NU 332/2-1, and G.Y. thanks MINECO (Spain) for supporting his research through different projects: AYA2012-31101, FPA2012-34694 and Consolider Ingenio SyeC CSD2007-0050
ProjectGobierno de España. AYA2012-31101; Gobierno de España. FPA2012-34694; Gobierno de España. CSD2007-0050; info:eu-repo/grantAgreement/EC/FP7/228398
SubjectsCosmology: theory; Galaxies: evolution; Galaxies: formation; Galaxies: structure; Methods: numerical; Astronomía; Física
NoteAstronomy and Astrophysics 577.(2015): A3 reproduced with permission from Astronomy & Astrophysics, © ESO
Rights© ESO 2015.
We study the two main constituent galaxies of a constrained simulation of the Local Group as candidates for the Milky Way (MW) and Andromeda (M31). We focus on the formation of the stellar discs and its relation to the formation of the group as a rich system with two massive galaxies, and investigate the effects of mergers and accretion as drivers of morphological transformations. We also assess the effects of varying the assumed feedback model on our results by running two different simulations, a first one where only supernova feedback is included and a second where we also model radiation pressure from stars. Methods. We use a state-of-the-art hydrodynamical code which includes star formation, feedback, and chemical enrichment to carry out our study. We use our two simulations, where we include or neglect the effects of radiation pressure from stars, to investigate the impact of this process on the morphologies and star formation rates of the simulated galaxies. Results. We find that the simulated M31 and MW have different formation histories, even though both inhabit, at z = 0, the same environment. These differences directly translate into and explain variations in their star formation rates, in situ fractions, and final morphologies. The simulated M31 candidate has an active merger history, as a result of which its stellar disc is unable to survive unaffected until the present time. In contrast, the MW candidate has a smoother history with no major mergers at late times, and forms a disc that grows steadily; at z = 0 the simulated MW has an extended, rotationally-supported disc that is dominant over the bulge. Our two feedback implementations predict similar evolutions of the galaxies and their discs, although some variations are detected, the most important of which is the formation time of the discs: in the model with weaker (stronger) feedback the discs form earlier (later). In summary, by comparing the formation histories of the two simulated galaxies, we conclude that the particular merger and accretion history of a galaxy rather than its environment at the LG-scales is the main driver of the formation and subsequent growth or destruction of galaxy discs
Google Scholar:Scannapieco, Cecilia - Creasey, Peter - Nuza, Sebastián E. - Yepes Alonso, Gustavo - Gottlöber, Stefan - Steinmetz, Matthias
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