Artistic vision of the Gaia spacecraft
The Gaia ESA spacecraft not only observes the billion stars of the Milky Way, but also captures extragalactic objects. Its automatic alert system signals with every transient event seen. A group of astronomers found out that by changing the existing automatic system, Gaia can be used to detect hundreds of specific transients in galactic centers. Thus, we managed to find about 480 cases per year. A new method is planned to be implemented in the near future, which will determine the exact nature of the events.
Apparatus Gaia launched in 2013 to measure the location of a billion stars of the Milky Way and tens of millions of galaxies. Each position in the sky is fixed once a month, reaching a total of 70 times during the mission. This allows you to capture transient events, such as the power of supermassive black holes or exploding supernovae. Gaia notices changes in brightness when a month later he studies the same sky region. Scientists have reported 500 transitional events in galactic centers seen in just one year. Astronomers examined the Gaia database from July 2016 to June 2017. They used the 12th edition of the catalog of galaxies from the SDSS (Sloan Digital Celestial Survey) and a special mathematical tool. The latter allows you to identify rare luminous events in the galactic centers.
The quick alert system plays an important role in the astronomical community for further research. Approximately 100 transients did not repeat in a month, which indicates a short period of action. These are especially valuable specimens, because they may indicate previously not found supermassive black holes. Perhaps we are talking about black holes of medium mass. Most of the events are explained by the process of feeding black holes that absorb material and “shine”. Experts are now using the William Herschel telescope to determine the true nature of the 480 finds.
