SOM of COSMOS2020 galaxies at z <  1.8, selected as described in Sect. 3.1. The same grid is color-coded in three different ways, to show the number of galaxies per cell (left panel), the similarity between galaxies in a given cell and the correspondent SOM weight (middle panel), and the MIPS-detected objects with M_LePh >  10¹⁰ M_⊙ (right panel). In each grid, empty cells are white. Left: handful of cells with only one or two objects are colored in gray. Middle: similarity is quantified by means of Eq. (2). Throughout this work, the dimensions of the 2D grid are arbitrarily labeled D₁ and D₂ since they have no physical meaning.