PASADENA, Calif. — The faint dwarf galaxies in a close-by galaxy group appear to have missed the memo. Instead of being dispersed evenly across the group’s most huge galaxy, which is what occurs in our personal galaxy group, these newly discovered dwarfs cluster in a single area. And astronomers don’t know why.
“This satellite distribution is just weird,” astronomer Eric Bell stated June 13 on the American Astronomical Society assembly.
Bell, of the University of Michigan in Ann Arbor, and colleagues used the Subaru telescope in Hawaii to hunt for faint clumps of stars, indicating dwarf galaxies, across the galaxy M81. This Milky Way–like galaxy is essentially the most distinguished member in a comparatively close by group of galaxies, all about 12 million light-years from Earth. The crew discovered one particular dwarf galaxy and 6 potential fainter ones.
Most of the identified satellite tv for pc galaxies (circled in crimson) within the M81 galaxy group, together with seven newfound candidates (yellow), appear to cluster towards one facet of the galaxy M81 (middle).Sloan Digital Sky Survey
“The part that’s just bananas,” Bell stated, is that the newfound satellite tv for pc galaxies all sit on one facet of M81.
Computer simulations of galaxy evolution recommend that the biggest galaxies have many faint, small galaxies sprinkled uniformly all through the outer a part of the dominant galaxy’s diffuse cloudlike halo. Observations in our galaxy group again this up: The dozens of dwarf galaxies identified to orbit within the Milky Way’s outskirts are distributed evenly across the galaxy, as are a lot of the dwarf galaxies seen round our nearest giant neighbor, the Andromeda Galaxy (SN: 3/11/15; SN: 8/19/15).
But within the M81 group, the seven newly recognized star clumps seem to encompass a smaller member of that group, NGC 3077, which is about one-tenth the mass of M81. “The fact that the bigger thing doesn’t have more satellites,” Bell says, “nobody expects that.”