The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744
Baugh, C. M.
Shan, H. Y.
AffiliationUniv Arizona, Steward Observ
Keywordsgravitational lensing: strong
gravitational lensing: weak
galaxies: clusters: individual: Abell 2744
MetadataShow full item record
PublisherOXFORD UNIV PRESS
CitationThe extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744 2016, 463 (4):3876 Monthly Notices of the Royal Astronomical Society
Rights© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
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AbstractWe present a joint optical/X-ray analysis of the massive galaxy cluster Abell 2744 (z = 0.308). Our strong- and weak-lensing analysis within the central region of the cluster, i.e. at R < 1 Mpc from the brightest cluster galaxy, reveals eight substructures, including the main core. All of these dark matter haloes are detected with a significance of at least 5 sigma and feature masses ranging from 0.5 to 1.4 x 10(14) M-circle dot within R < 150 kpc. Merten et al. and Medezinski et al. substructures are also detected by us. We measure a slightly higher mass for the main core component than reported previously and attribute the discrepancy to the inclusion of our tightly constrained strong-lensing mass model built on Hubble Frontier Fields data. X-ray data obtained by XMM-Newton reveal four remnant cores, one of them a new detection, and three shocks. Unlike Merten et al., we find all cores to have both dark and luminous counterparts. A comparison with clusters of similar mass in the Millennium XXL simulations yields no objects with as many massive substructures as observed in Abell 2744, confirming that Abell 2744 is an extreme system. We stress that these properties still do not constitute a challenge to Lambda cold dark matter, as caveats apply to both the simulation and the observations: for instance, the projected mass measurements from gravitational lensing and the limited resolution of the subhaloes finders. We discuss implications of Abell 2744 for the plausibility of different dark matter candidates and, finally, measure a new upper limit on the self-interaction cross-section of dark matter of sigma(DM) < 1.28 cm(2) g(-1) (68 per cent CL), in good agreement with previous results from Harvey et al.
VersionFinal published version
SponsorsScience and Technology Facilities Council [ST/L00075X/1, ST/K501979/1]; BIS National E-infrastructure capital grant [ST/K00042X/1]; STFC [ST/H008519/1]; STFC DiRAC Operations grant [ST/K003267/1]; Durham University; Mesocentre d'Aix-Marseille Universite [14b030]; Swiss National Science Foundation (SNSF); Leverhulme Trust; Royal Society; Australian Research Council through Future Fellowship [FT140100255]; Marie-Curie International Incoming Fellowship [FP7-PEOPLE-2012-IIF/327561]; NSFC of China ; ERC advanced grant LIDA; ERC starting grant CALENDS; CIG grant ; Centre National de la Recherche Scientifique (CNRS); National Science Foundation [AST-1044455]; Space Telescope Science Institute [HST-AR-12144.01-A]; Swiss National Science Foundation