Contrary to what is established by the standard model, dark matter may indeed be self-interacting. This was the conclusion of a new piece of research published in "Astronomy & Astrophysics" (A&A) and conducted by Riccardo Valdarnini of SISSA's Astrophysics and Cosmology group. Using numerical simulations, the study analysed what happens in-side "El Gordo" (literally "The Fat One" in Spanish), a giant cluster merger seven billion light years away from us. The calculations indicated that in this cluster the observed physical separation between the points of maximum density of Dark Matter and those of the other mass components can be explained using the so-called SIDM (Self-Interacting dark matter) model, as opposed to the standard one. This research makes an important contribution in favour of the SIDM model, according to which dark matter particles exchange energy through collisions, with interesting astrophysical repercussions.
((Image by NASA, ESA, CSA, J. Diego (Instituto de Física de Cantabria), B. Frye (University of Arizona), P. Kamieneski (Arizona State University), T. Carleton (Arizona State University), and R. Windhorst (University of Arizona), A. Pagan (STScI), J. Summers (Arizona State University), J. D’Silva (University of Western Australia), A. Koekemoer (STScI), A. Robotham (University of Western Australia), and R. Windhorst (University of Arizona))