Characterizing Intra-cluster light in the Hubble Frontier Fields

Understand

We investigate the intra-cluster light (ICL) in the 6 Hubble Frontier Field clusters at $0.3<z<0.6$.

• We employ a new method, which is free from any functional form of the ICL profile, and exploit the unprecedented depth of this Hubble Space Telescope imaging to map the ICL's diffuse light out to clustrocentric radii $R\sim300$kpc ($\mu_{\rm ICL}\sim27$mag arcsec$^{-2}$).
• From these maps, we construct radial color and stellar mass profiles via SED fitting and find clear negative color gradients in all systems with increasing distance from the Brightest Cluster Galaxy (BCG).
• While this implies older/more metal rich stellar components in the inner part of the ICL, we find the ICL mostly consists of a $<2$Gyr population, and plausibly originated with $\log M_*/M_\odot<10$ cluster galaxies.