The Formation of Large Galaxy Disks in Low z Major Mergers

Type Conference Paper
Names Alyson Brooks, F. Governato, C. Brook, L. Mayer, B. Willman, P. Jonsson, A. Stilp, L. Pope, C. Christensen, J. Wadsley, T. Quinn
Proceedings Title Bulletin of the American Astronomical Society
Conference Name American Astronomical Society AAS Meeting #214, #308.05
Volume 41
Pages 737
Date May 1, 2009
Library Catalog NASA ADS
Abstract Using high resolution SPH simulations in a fully cosmological LambdaCDM context we study the formation of a bright disk dominated galaxy that originates from a "wet" major merger at z=0.8. A substantial thin stellar disk grows rapidly following the last major merger and the present day properties of the final remnant are typical of early type spiral galaxies. The key ingredients for the formation of a dominant stellar disk component after a major merger are: i) substantial and rapid accretion of gas through cold flows followed at late times by cooling of gas from the hot phase, ii) supernova feedback that is able to partially suppress star formation during mergers, and iii) relative fading of the spheroidal component. The gas fraction of the progenitor disks does not exceed 25% at z < 3, emphasizing that the continuous supply of gas from the local environment plays a major role in the regrowth of disks and in keeping the galaxies blue. The results of this simulation alleviate the problem posed for the existence of disk galaxies by the high likelihood of interactions and mergers for galaxy sized halos at relatively low z.
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