In addition to nearly one billion stars in the Milky Way, the European Space Agency's Gaia mission also observes extragalactic objects. The spacecraft's automated warning system notifies astronomers of the detection of so-called "transients", or short-lived flares. In a new scientific work, the team of astronomers discovered that by adjusting the algorithms of the existing automated warning system, the Gaia apparatus can be used to detect hundreds of unusual transients in the centers of galaxies. The researchers found approximately 480 transients over a period of approximately one year. This new method may be adopted in the near future, allowing astronomers to determine the nature of these mysterious events.
Researchers led by Zuzanna Kostrzewa-Rutkowska from the Netherlands Institute for Space Research searched the Gaia mission database for transients observed near galactic nuclei between July 2016 and June 2017. They used the catalog galaxies - from Data Release # 12 of the Sloan Digital Sky Survey - and a proprietary mathematical method. This new mathematical tool has allowed astronomers to identify rare flares near the centers of galaxies. Kostrzeva-Rutkovskaya and her colleagues identified 480 such events, of which only five events were previously recognized by the Gaia spacecraft's automated warning system.
The study of such short-term flares is of great interest to astronomers, since these flares are often associated with events such as the absorption of a star that came too close to it by a black hole - and these events, in turn, can help detect rare black holes of intermediate masses, which, while staying at rest, are not visible through the lenses of telescopes, the authors explained.
The research is published in the Monthly Notices of the Royal Astronomical Society.