For the first time, astronomers have detected the echo of the death of a supermassive black hole. The observations were carried out in the region of the Arp 187 galaxy.
In the hearts of galaxies like the Milky Way, there are supermassive black holes whose mass is millions or even billions of times the mass of the Sun.
Some of these supermassive black holes are active galactic nuclei (AGNs). They emit large amounts of radiation – X-rays and radio waves. AGNs are responsible for the double jets of ionized gas that are visible in many galaxies.
Scientists do not fully understand how AGNs go out, but a new study of the Arp 187 galaxy brings them closer to solving.
AGN usually produces a large number of X-rays. However, data from the NuSTAR telescope showed that the galactic core Arp 187 has darkened over the past several thousand years.
Arp 187 spans 3,000 light-years. This means that the trail of leaving matter is visible for millennia after the “death” of the galactic nucleus. Astronomers call this trail a “light echo” and compare it to smoke from a freshly extinguished fire.
The researchers called their discovery “accidental.” Arp 187 could be a stepping stone to learning more about what happens at the end of AGN’s life, scientists say.