In addition to providing crucial restrictions on dark matter features, the study of dynamically cold stellar streams provides insights into the gravitational potential in which they live. Nevertheless, these streams are intrinsically faint, making it extremely difficult to detect them outside local contexts.
A new study reports the discovery of a giant and highly faint stream of stars between galaxies. Although streams within our galaxy and in other galaxies were previously discovered, this is the first instance of a stream running across galaxies. This stream is the biggest one found thus far.
This extremely faint stellar stream- named ‘Giant Coma Stream’- with an extraordinarily coherent and thin morphology is spotted in the Coma Galaxy Cluster. It spans ∼510 kpc in length and appears as a free-floating structure.
The initial observations were conducted in California (United States of America) using astronomer Michael Rich’s comparatively small 70-centimeter telescope. The 4.2-meter William Herschel telescope in La Palma, Spain, was then directed toward the region by the researchers. Following image processing, scientists observed a remarkably faint stream that was longer than the Milky Way by more than ten times. The stream does not seem to be connected to any one galaxy; instead, it appears to be floating amid the cluster environment.
Lead researcher Javier Román said, “This giant stream crossed our path by coincidence. We were studying halos of stars located around large galaxies.”
Co-author Reynier Peletier (University of Groningen, the Netherlands) explains, “The discovery is a rather fragile structure amid a hostile environment of mutually attracting and repelling galaxies. Meanwhile, we have simulated such huge flows in the computer. We therefore expect to find more of them. For example, if we search with the future 39-meter ELT and when Euclid starts producing data.”
The scientists expect giant telescopes in the future, not just to find new huge streams. In addition, they wish to zoom in on the image of the Giant Coma Stream.