A free-form lensing model of A370 revealing stellar mass dominated BCGs, in Hubble Frontier Fields images

JL acknowledges a grant from the Seed Funding for Basic Research of the University of Hong Kong (Project No. 201411159166) for this work. JMD acknowledges support of the projects AYA2015-64508-P (MINECO/FEDER, UE), AYA2012-39475-C02-01 and the consolider project CSD2010-00064 funded by the Ministerio de Economia y Competitividad. JL acknowledges, on behalf of his co-I’s, support from the Research Grants Council of Hong Kong through grant 17319316.