An article published in the journal “Astrophysical Journal” describes the study of a sort of echo generated by a gamma-ray burst cataloged as GRB 161219B emitted by a newborn black hole. The gamma-ray emissions lasted only seven seconds but emissions at other electromagnetic frequencies lasted even for weeks, which enabled a team of astronomers to use the ALMA radio telescope to study the ones at millimeter wavelengths. They offered other information on the gamma-ray burst and on the characteristics of its powerful jets.