Schaller, Matthieu and Robertson, Andrew and Massey, Richard and Bower, Richard G. and Eke, Vincent R. (2015) 'The offsets between galaxies and their dark matter in Λ cold dark matter.', Monthly notices of the Royal Astronomical Society : letters., 453 (1). L58-L62.
We use the ‘Evolution and Assembly of GaLaxies and their Environments’ (EAGLE) suite of hydrodynamical cosmological simulations to measure offsets between the centres of stellar and dark matter components of galaxies. We find that the vast majority (>95 per cent) of the simulated galaxies display an offset smaller than the gravitational softening length of the simulations (Plummer-equivalent ϵ = 700 pc), both for field galaxies and satellites in clusters and groups. We also find no systematic trailing or leading of the dark matter along a galaxy's direction of motion. The offsets are consistent with being randomly drawn from a Maxwellian distribution with σ ≤ 196 pc. Since astrophysical effects produce no feasible analogues for the 1.62+0.47−0.49 kpc offset recently observed in Abell 3827, the observational result is in tension with the collisionless cold dark matter model assumed in our simulations.
|Keywords:||Astroparticle physics, Cosmology: theory, Dark matter.|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1093/mnrasl/slv104|
|Publisher statement:||This article has been accepted for publication in Monthly notices of the Royal Astronomical Society: letters. ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Date accepted:||22 July 2015|
|Date deposited:||05 November 2015|
|Date of first online publication:||October 2015|
|Date first made open access:||No date available|
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