Ultra-faint stellar systems discovered toward the Sagittarius stream
Image Credit: K. Vivas & CTIO/NOAO/AURA/NSF
Astronomers have discovered ultra-faint stellar systems in the direction of the Sagittarius stream, the stream of stars that is being pulled out of the Sagittarius dwarf galaxy as it interacts gravitationally with our own Milky Way galaxy (Figure 1, left). Similar in size to globular clusters but more than 100 times fainter, the new stellar systems straddle the fuzzy boundary between dwarf galaxies and stellar clusters and belong to an emerging class of ultra-faint, compact stellar systems (Figure 2, right). The discoveries were made by a team using data from the Dark Energy Survey, which is being carried out with DECam on the Blanco telescope at CTIO. The team was leaded by Elmer Luque from Universidade Federal do Rio Grande do Sul, Brazil, and includes NOAO astronomers Kathy Vivas, Tim Abbott, David James, Chris Smith and Alistair Walker.
Link to preprint: http://xxx.lanl.gov/pdf/1608.04033v1