The Subaru telescope recorded 11 dwarf galaxies and 2 star halos in the outer area of a large whale-type galaxy, 25 million light-years distant from us. This review allows a new study of the formation of tidal stellar flows.
Scientists from the University of Tohoku have used the Subaru telescope's ultra-wide field of view to better understand star halos. These are ring-shaped star collections spanning large galaxies and often originating from small dwarf types.
Special attention was focused on NGC 4631 (Keith). In its outer region, 11 dwarf galaxies were identified, some of which were already listed in catalogs. This type is difficult to find due to its small size, low mass and dullness. The survey also depicted two tidal star streams circling around the galaxy: Jet SE and Jet NW. The researchers believe that the streams were formed due to the gravitational contact between the whale and the rotating dwarf galaxy.
Dwarf galaxies found in the survey. Three color images are characterized by HSC-g and HSC-i images. False image with intermediate color - averaged HSC-g and HSC-i. The object at the top right was previously considered a dwarf galaxy, but a new survey showed that this overlap of foreground stars and background galaxies
They also found out that both streams are relatively weaker than those that form near the Milky Way. NW jet is brighter and has a more concentrated core. It is believed that stellar halos are less common if the total stellar mass of the galaxy is less than in large galaxies, such as the Triangle. But the object is still actively expanding with halos.