We present high-precision strong lensing models for the galaxy clusters MACS J0416.1–0403 at z=0.396 and Abell 2744 at z=0.307. The models are constrained by two of the largest data-sets of secure multiple images ever used in lensing. These are identified from the photometric images observed by the Hubble space telescope and JWST in combination with spectroscopic data obtained by the Multi-Unit Spectroscopic Explorer at the Very Large Telescope. The same spectro-photometric data are used to create pure and complete samples of cluster member galaxies. Our models allow an extremely precise estimation of the cluster total mass distribution and produce accurate magnification maps that are fundamental to study the physical properties (mass, size, luminosity, etc.) of the lensed high-redshift galaxies.

The full relativistic dielectric tensor for a Maxwellian plasma in the electron-cyclotron range of frequencies is investigated. A new representation for arbitrary values of the wave frequency and direction of propagation of the anti-Hermitian part is presented that avoids the standard expansions of the Bessel functions. A compact form of the wave damping for ω ≽ 2ωc is obtained that is useful for the investigation of synchrotron radiation in hot plasmas.