...isolated, whereas others gather in big numbers (over a hundred) to form clusters. While the exact definition of what a protocluster actually is has yet to be agreed upon, it is generally used to refer to a group of very young galaxies that will merge...
... a young, but fully formed galaxy cluster," said co-author David Elbaz from CEA. Until now, only protoclusters – loose collections of galaxies – have been recorded farther away than the CL J1001, making this cluster the...