Image Details

Choose export citation format:

Apocenter Pile-up: Origin of the Stellar Halo Density Break

  • Authors: Alis J. Deason, Vasily Belokurov, Sergey E. Koposov, and Lachlan Lancaster

2018 The Astrophysical Journal Letters 862 L1.

  • Provider: AAS Journals

Caption: Figure 3.

Apocenter and pericenter distributions of the local main sequence stars (top panels) and distant BHB stars (bottom panels). We show the 2D distributions for metal-rich ([Fe/H] > −1.5) and metal-poor ([Fe/H] < −2) stars in the left and middle panels. The metal-rich minus metal-poor difference is shown in the right panels. Here, gray indicates no difference, black is an excess of metal-rich stars, and white is an excess of metal-poor stars. Tracks of constant eccentricity (e = 0, 0.5, 0.9) are shown with the dotted red lines, and the vertical orange lines indicated the approximate break radius of the stellar halo (Deason et al. 2011). In both the local and distant samples two clear residuals stand out in the metal-rich stars: (1) the disk population with e ∼ 0 (for the BHB sample, the “disk” population is likely supplied by a small number of contaminating blue stragglers), and (2) a population with very high eccentricity (e ∼ 0.9) and apocenters coincident with the break radius—the “sausage” stars.

Other Images in This Article
Copyright and Terms & Conditions