Disentangling the ICL with the CHEFs: Abell 2744 as a case study
  Measurements of the intracluster light (ICL) are still prone to
methodological ambiguities and there are multiple techniques in the literature
for that purpose, mostly based on the binding energy, the local density
distribution, or the surface brightness. A common issue with these methods is
the a priori assumption of a number of hypotheses on either the ICL morphology,
its surface brightness level or some properties of the brightest cluster galaxy
(BCG). The discrepancy on the results is high, and numerical simulations just
bound the ICL fraction in present-day galaxy clusters to the range 10-50%. We
developed a new algorithm based on the Chebyshev-Fourier functions (CHEFs) to
estimate the ICL fraction without relying on any a priori assumption on the
physical or geometrical characteristics of the ICL. We are able to not only
disentangle the ICL from the galatic luminosity but mark out the limits of the
BCG from the ICL in a natural way. We test our tecnique with the recently
released data of the cluster Abell 2744, observed by the Frontier Fields
program. The complexity of this multiple merging cluster system and the
formidable depth of these images make it a challenging test case to prove the
efficiency of our algorithm. We found a final ICL fraction of 19.17+-2.87%,
which is very consistent with numerical simulations.
