An Orphan No Longer? Detection of the Southern Orphan Stream and a Candidate Progenitor

October 2015 • 2015ApJ...812L..26G

Authors • Grillmair, Carl J. • Hetherington, Lauren • Carlberg, Raymond G. • Willman, Beth

Abstract • Using a shallow, two-color survey carried out with the Dark Energy Camera, we detect the southern, possibly trailing arm of the Orphan Stream. The stream is reliably detected to a decl. of -38°, bringing the total known length of the Orphan Stream to 108°. We find a slight offset or “S” shape in the stream at δ ≃ -14° that would be consistent with the transition from leading to trailing arms. This coincides with a moderate concentration of 137 ± 25 stars (to g = 21.6) that we consider a possible remnant of the Orphan progenitor. The position of this feature is in agreement with previous predictions.


IPAC Authors


Carl Grillmair

Associate Scientist