Unveiling the formation and evolution of galaxy clusters through the intracluster light and multidisciplinar techniques of image processing and big data analysis

ended

The intracluster light (ICL) is defined as the luminous component of the clusters of galaxies which is formed by stars that are gravitationally bound to the cluster potential but do not belong to any galaxy in particular. Its properties give insights on cluster formation and evolution, determine the dynamical stage of the system, estimate its age, improve scaling relations, and constrain the cosmological parameters. Its study is limited because the ICL has a very low surface brightness and traditional techniques assume different a priori hypotheses that bias the final results. As a consequence, ICL studies are rare and often draw inconsistent (or even contradictory) conclusions and results. We developed and tested successfully the first algorithm to analyze images of galaxy clusters and measure ICL properties completely free of a priori assumptions, called CICLE. CICLE gathers mathematical tools of image modelling and characterisation, and algorithms of multiresolution analysis. Some of these tools were developed in-house and are multidisciplinar. Our goal is to carry out the first extensive, systematic, and consistent study of the ICL in groups and clusters of galaxies using CICLE and high-quality data from HST and the J-PAS project. We plan to split the study in three subprojects, according to the characteristics of the systems: i) massive clusters, ii) non-massive clusters and groups, and iii) fossil groups. This work would report: a) observationally, images and data of high scientific impact, attractive to different astronomical areas, b) analytically, new and versatile techniques of big data analysis, with potential to be widely used not only in Astronomy but also in other fields as Geophysics, Medicine, or Biochemistry, and c) scientifically, the first unbiased and large-scale characterization of the ICL and the discovery of the effect of this component on the process of formation and evolution of clusters of galaxies, still unknown.