Evidence for a vast prograde stellar stream in the solar vicinity

  title={Evidence for a vast prograde stellar stream in the solar vicinity},
  author={Lina Necib and Bryan Ostdiek and Mariangela Lisanti and Timothy Cohen and Marat Freytsis and Shea Garrison-Kimmel and Philip F. Hopkins and Andrew R. Wetzel and Robyn E. Sanderson},
  journal={Nature Astronomy},
Massive dwarf galaxies that merge with the Milky Way on prograde orbits can be dragged into the disk plane before being completely disrupted. Such mergers can contribute to an accreted stellar disk and a dark matter disk. Here we present Nyx, a vast stellar stream in the vicinity of the Sun, which provides the first indication that such an event occurred in the Milky Way. We identify about 200 stars that have coherent radial and prograde motion in this stream using a catalogue of accreted stars… 
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