Galaxy Cluster Lensing Masses in Modified Lensing Potentials


We determine the concentration-mass relation of 19 X-ray selected galaxy clusters from the Cluster Lensing and Supernova Survey with Hubble survey in theories of gravity that directly modify the lensing potential. We model the clusters as Navarro-Frenk-White haloes and fit their lensing signal, in the Cubic Galileon and Nonlocal gravity models, to the lensing convergence profiles of the clusters. We discuss a number of important issues that need to be taken into account, associated with the use of non-parametric and parametric lensing methods, as well as assumptions about the background cosmology. Our results show that the concentration and mass estimates in the modified gravity models are, within the error bars, the same as in Λ cold dark matter. This result demonstrates that, for the Nonlocal model, the modifications to gravity are too weak at the cluster redshifts, and for the Galileon model, the screening mechanism is very efficient inside the cluster radius. However, at distances ~ (2-20) Mpc h⁻¹ from the cluster centre, we find that the surrounding force profiles are enhanced by similar to 20-40 per cent in the Cubic Galileon model. This has an impact on dynamical mass estimates, which means that tests of gravity based on comparisons between lensing and dynamical masses can also be applied to the Cubic Galileon model.



Gravitational lenses, Galaxies--Clusters--Abell 2744, Cosmology, Galactic halos, Gravity, Dark energy (Astronomy)

This work was supported by the Science and Technology Facilities Council (grant number ST/L00075X/1). This work used the DiRAC Data Centric system at Durham University, operated by the Institute for Computational Cosmology on behalf of the STFC DiRAC HPC Facility ( This equipment was funded by BIS National E-infrastructure capital grant ST/K00042X/1, STFC capital grant ST/H008519/1, STFC DiRAC Operations grant ST/K003267/1 and Durham University. DiRAC is part of the National EInfrastructure. AB is supported by FCT-Portugal through grant SFRH/BD/75791/2011. EJ is supported by Fermi Research Alliance, LLC under the US Department of Energy under contract no. DE-AC02-07CH11359. LK thanks theUniversity of Texas at Dallas for support. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013) under REA grant agreement number 627288. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant NuMass Agreement no. [617143]. This work has been partially supported by the European Union FP7 ITN INVISIBLES (Marie Curie Actions, PITN- GA- 2011- 289442) and STFC.


©2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.