Astronomers have for the first time detected a stellar stream from a globular cluster outside our galaxy, opening a new way to map invisible dark matter, reports infohub.kz.
An international team of researchers, including specialists from Northwestern University, the University of Copenhagen, and the Technical University of Denmark, found a faint stellar ribbon around the ultra-diffuse galaxy UGC 9050-Dw1, located about 115 million light-years from Earth. This is the first observation of a stellar stream from a globular cluster beyond the Milky Way.
The structure formed as a result of the disruption of an ancient star cluster by the host galaxy's gravity. The discovery was made while analyzing archival images from the Hubble Space Telescope, with the key detail spotted by astronomer David Hendel.
The stars in the stream move along a common orbit shaped by the gravitational field. By modeling the motion of the stars, the researchers reconstructed the galaxy's gravitational field and calculated the distribution of invisible dark matter. The authors of the study, including Julie Køl Holm and Tjitske Starkenburg, note that this method confirmed the applicability of stellar streams for studying mysterious mass in the outer universe.