Scientists at Tohoku University in Japan have discovered a dying active galactic nucleus (AYAG), in the center of which is a supermassive black hole. The researchers presented their discovery at the annual conference of the American Astronomical Society.
Astronomers recorded a relativistic jet bursting out from the Arp 187 galaxy, which is a hallmark of the presence of an active nucleus. The discovery was made using the ALMA (Atacama Large Millimeter Array) and VLA (Very Large Array) radio telescope complexes. However, during further observations at different wavelengths, the scientists did not notice any activity in the galactic core itself, indicating that the AYAG in Arp 187 had already died out.
Once the ANG “dies,” the visible small components of the active core become faint because the light sources fade. However, the large-scale region of ionized gas in Arp 187 is still visible because it takes about three thousand years for photons to reach the edge of the region. This phenomenon is known as the light echo. The nucleus itself has become more than a thousand times fainter in all wavebands.
Nuclei are nuclei in which processes occur that release enormous amounts of energy. It is believed that the source of high-energy radiation is supermassive black holes, which also generate jets.