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Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2015

The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827

Richard Massey
Liliya Williams
Renske Smit
  • Fonction : Auteur
Thomas D. Kitching
  • Fonction : Auteur
David Harvey
Mathilde Jauzac
Douglas Clowe
  • Fonction : Auteur
Alastair Edge
  • Fonction : Auteur
Matt Hilton
  • Fonction : Auteur
Eric Jullo
Jori Liesenborgs
  • Fonction : Auteur
Julian Merten
  • Fonction : Auteur
Irshad Mohammed
  • Fonction : Auteur
Daisuke Nagai
  • Fonction : Auteur
Andrew Robertson
Prasenjit Saha
  • Fonction : Auteur
Rebecca Santana
  • Fonction : Auteur
John Stott
  • Fonction : Auteur
Eric Tittley
  • Fonction : Auteur

Résumé

Galaxy cluster Abell 3827 hosts the stellar remnants of four almost equally bright elliptical galaxies within a core of radius 10 kpc. Such corrugation of the stellar distribution is very rare, and suggests recent formation by several simultaneous mergers. We map the distribution of associated dark matter, using new Hubble Space Telescope imaging and Very Large Telescope/Multi-Unit Spectroscopic Explorer integral field spectroscopy of a gravitationally lensed system threaded through the cluster core. We find that each of the central galaxies retains a dark matter halo, but that (at least) one of these is spatially offset from its stars. The best-constrained offset is 1.62(-0.49)(+0.47) kpc, where the 68 per cent confidence limit includes both statistical error and systematic biases in mass modelling. Such offsets are not seen in field galaxies, but are predicted during the long infall to a cluster, if dark matter self-interactions generate an extra drag force. With such a small physical separation, it is difficult to definitively rule out astrophysical effects operating exclusively in dense cluster core environments - but if interpreted solely as evidence for self-interacting dark matter, this offset implies a cross-section sigma(DM)/(m) similar to (1.7 +/- 0.7) x 10(-4) cm(2) g(-1) x (t(infall)/10(9) yr)(-2), where t(infall) is the infall duration.

Dates et versions

hal-01439994 , version 1 (18-01-2017)

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Citer

Richard Massey, Liliya Williams, Renske Smit, Mark Swinbank, Thomas D. Kitching, et al.. The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827. Monthly Notices of the Royal Astronomical Society, 2015, 449 (4), pp.3393--3406. ⟨10.1093/mnras/stv467⟩. ⟨hal-01439994⟩
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