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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827
AU - Massey, Richard
AU - Williams, Liliya
AU - Smit, Renske
AU - Swinbank, Mark
AU - Kitching, Thomas D.
AU - Harvey, David
AU - Jauzac, Mathilde
AU - Israel, Holger
AU - Clowe, Douglas
AU - Edge, Alastair
AU - Hilton, Matt
AU - Jullo, Eric
AU - Leonard, Adrienne
AU - Liesenborgs, Jori
AU - Merten, Julian
AU - Mohammed, Irshad
AU - Nagai, Daisuke
AU - Richard, Johan
AU - Robertson, Andrew
AU - Saha, Prasenjit
AU - Santana, Rebecca
AU - Stott, John
AU - Tittley, Eric
PY - 2015/6/1
Y1 - 2015/6/1
N2 - 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.
AB - 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.
KW - astroparticle physics
KW - gravitational lensing: strong
KW - galaxies: clusters: individual: Abell 3827
KW - dark matter
KW - HUBBLE-SPACE-TELESCOPE
KW - LENSING MASS RECONSTRUCTION
KW - STELLAR POPULATION SYNTHESIS
KW - CHARGE-TRANSFER INEFFICIENCY
KW - PIXEL-BASED CORRECTION
KW - LARGE-SCALE STRUCTURE
KW - ADVANCED CAMERA
KW - NONPARAMETRIC INVERSION
KW - GENETIC ALGORITHM
KW - CROSS-SECTION
U2 - 10.1093/mnras/stv467
DO - 10.1093/mnras/stv467
M3 - Journal article
VL - 449
SP - 3393
EP - 3406
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -