The shape of dark matter haloes in the Aquarius simulations: Evolution and memory

C.A. Vera-Ciro, L. V. Sales, A. Helmi

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

We use the high resolution cosmological N-body simulations from the Aquarius project to investigate in detail the mechanisms that determine the shape of Milky Way-type dark matter haloes. We find that, when measured at the instantaneous virial radius, the shape of individual haloes changes with time, evolving from a typically prolate configuration at early stages to a more triaxial/oblate geometry at the present day. This evolution in halo shape correlates well with the distribution of the infalling material: prolate configurations arise when haloes are fed through narrow filaments, which characterizes the early epochs of halo assembly, whereas triaxial/oblate configurations result as the accretion turns more isotropic at later times. Interestingly, at redshift z = 0, clear imprints of the past history of each halo are recorded in their shapes at different radii, which also exhibit a variation from prolate in the inner regions to triaxial/oblate in the outskirts. Provided that the Aquarius haloes are fair representatives of Milky Way-like 1012Msun objects, we conclude that the shape of such dark matter haloes is a complex, time-dependent property, with each radial shell retaining memory of the conditions at the time of collapse.
Original languageEnglish
Title of host publicationAssembling the Puzzle of the Milky Way
Subtitle of host publicationEPJ Web of Conferences
EditorsC Reyle, A Robin, M Schultheis
PublisherE D P SCIENCES
Number of pages2
Volume19
ISBN (Print)978-2-7598-0718-5
DOIs
Publication statusPublished - Feb-2012
EventConferences of the Assembling the Puzzle of the Milky Way - , France
Duration: 17-Apr-201122-Apr-2011

Publication series

NameEPJ Web of Conferences
PublisherE D P SCIENCES
Volume19
ISSN (Print)2100-014X

Other

OtherConferences of the Assembling the Puzzle of the Milky Way
CountryFrance
Period17/04/201122/04/2011

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