An international team led by Yuli Kil Holm of the Niels Bohr Institute and Sarah Pearson of DTU Space has for the first time detected a stellar stream from a globular cluster outside our galaxy. The findings were published in the journal "Nature", and the discovery confirmed the effectiveness of a new method for studying the mass of the Universe, infohub.kz reports.
A stellar stream is a long, narrow trail of stars pulled from a dense globular cluster by the tidal forces of its host galaxy. Because of their extremely faint glow, such structures had previously been analyzed only in the Milky Way. This object was found inside the ultra-diffuse galaxy UGC9050-Dw1, which has exceptionally low brightness.
Since the shape and motion of stellar streams depend directly on gravity, they serve as unique indicators for studying the distribution of hidden mass. The study's authors performed new calculations of the total mass of the galaxy UGC9050-Dw1 and confirmed that it contains a colossal amount of dark matter, which accounts for up to 85% of all matter in the Universe.
According to the authors, the successful application of this method beyond the Milky Way opens broad opportunities for astrophysics. In the future, the new space telescopes "Euclid" and "Nancy Grace Roman" will make it possible to find similar stellar streams in other types of galaxies, helping scientists get closer to unraveling the nature of dark matter.