Optical and near-infrared light curves of the kilonova AT 2017gfo

The light curve of illustrates the rapid optical decline expected for all electromagnetic counterparts of NS-NS and NS-BH mergers. These rare transients remain brighter for longer time at near-infrared wavelengths, reaching their peak a few days after the merger in this wavelength regime. This characteristic makes wide-field near-infrared imaging a fundamental tool to better identify these objects and to study them in detail.