The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744

M. Jauzac, D. Eckert, J. Schwinn, D. Harvey, C. M. Baugh, A. Robertson, S. Bose, R. Massey, M. Owers, H. Ebeling, H. Y. Shan, E. Jullo, J. P. Kneib, J. Richard, H. Atek, B. Clément, E. Egami, H. Israel, K. Knowles, M. LimousinP. Natarajan, M. Rexroth, P. Taylor, C. Tchernin

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


We 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 5s and feature masses ranging from 0.5 to 1.4 × 1014 M⊙ 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 similarmass 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 Λ 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 σDM < 1.28 cm2 g-1 (68 per cent CL), in good agreement with previous results from Harvey et al.

Original languageEnglish (US)
Pages (from-to)3876-3893
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Dec 21 2016


  • Galaxies: clusters: individual: Abell 2744
  • Gravitational lensing: strong
  • Gravitational lensing: weak

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744'. Together they form a unique fingerprint.

Cite this