Abstract
We use data from the Pan-STARRS1 survey to present a panoramic view of the Sagittarius tidal stream in the southern Galactic hemisphere. As a result of the extensive sky coverage of Pan-STARRS1, the southern stream is visible along more than 60 degrees of its orbit, nearly double the length seen by the SDSS. The recently discovered southern bifurcation of the stream is also apparent, with the fainter branch of the stream visible over at least 30 degrees. Using a combination of fitting both the main sequence turn-off and the red clump, we measure the distance to both arms of the stream in the south. We find that the distances to the bright arm of the stream agree very well with the N-body models of Law & Majewski (2010). We also find that the faint arm lies ~5 kpc closer to the Sun than the bright arm, similar to the behavior seen in the northern hemisphere.
Highlights
The past decade has seen a tremendous growth in the amount of known tidal substructure in the Galactic halo (Ibata et al 2001; Newberg et al 2002; Yanny et al 2003; Martin et al 2004; Grillmair & Dionatos 2006; Grillmair 2006; Belokurov et al 2007a, 2007b; Juricet al. 2008)
Comparing their results to ours for the bright arm of the stream, there is a clear difference of 7–10 kpc, which is consistent along the length of the stream
We have used data from Pan-STARRS1 to show the spatial extent of the Sgr stream over 60◦ of its orbit in the southern Galactic hemisphere
Summary
The Harvard community has made this article openly available. Please share how this access benefits you. “A Pan-STARRS1 View of the Bifurcated Sagittarius Stream.”. The Astrophysical Journal 762 (1) (December 7): 6.
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