The Vera C. Rubin Observatory, recently completed on Cerro Pachón in the Chilean Andes, has found two faint companions of the Milky Way that no earlier telescope had seen. The discoveries came from preview data gathered before the observatory officially started its survey.
The first is Aquarius IV, a tiny galaxy about 355,000 light-years away in the far outskirts of our galaxy. The second, Rubin-GC1, is a star cluster on the opposite side of the Milky Way, tucked behind thick clouds of cosmic dust that make observation especially hard.
Astronomers know of roughly 65 satellite galaxies around the Milky Way, and some estimates suggest hundreds more are still hiding. Yale astronomy student William Cerny, lead author of the Aquarius IV study, said that if Rubin can find systems this faint with preview data, its full survey should reveal many more.
Rubin began its 10-year Legacy Survey of Space and Time in June. Researchers hope the new satellites will help them test models of galaxy formation and learn more about dark matter.
