http://arxiv.org/abs/1804.11347
We explore the phase-space structure of nearby halo stars identified kinematically from Gaia DR2 data. We focus on their distribution in velocity and in
integrals of motion' space as well as on their photometric properties. Our sample of stars selected relatively strictly from the Toomre diagram, contains an important contribution from the low rotational velocity tail of the disk(s). The VR-distribution of these stars depicts a small asymmetry similar to that seen for the faster rotating thin disk stars near the Sun. We also identify a prominent, slightly retrogradeblob’, which traces the metal-poor halo main sequence reported by Gaia Collaboration et al. (2018d). We also find many small clumps especially noticeable in the tails of the velocity distribution of the stars in our sample. Their HR diagrams disclose narrow sequences characteristic of simple stellar populations. This stream-frosting confirms predictions from cosmological simulations, namely that substructure is most apparent amongst the fastest moving stars, typically reflecting more recent accretion events.
H. Koppelman, A. Helmi and J. Veljanoski
Tue, 1 May 18
54/78
Comments: 5 pages, 5 figures, submitted to ApJL
You must be logged in to post a comment.