Two substructures in the nearby stellar halo found in Gaia and RAVE

Hefan Li; Cuihua Du; Yanbin Yang; Heidi Jo Newberg; Jun Ma; Jianrong Shi; Yunsong Piao

doi:10.3847/1538-4357/ab8733

Two substructures in the nearby stellar halo found in Gaia and RAVE

Astrophysics of Galaxies 2020-10-28 v1

Authors: Hefan Li , Cuihua Du , Yanbin Yang , Heidi Jo Newberg , Jun Ma , Jianrong Shi , Yunsong Piao

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Abstract

We use the second Gaia data release (Gaia DR2), combined with RAVE spectroscopic surveys, to identify the substructures in the nearby stellar halo. We select 3,845 halo stars kinematically and chemically, and determine their density distribution in energy and angular momentum space. To select the substructures from overdensities, we reshuffle the velocities and estimate their significance. Two statistically significant substructures, GR-1 and GR-2, are identified. GR-1 has a high binding energy and small $z$ -angular momentum. GR-2 is metal-rich but retrograde. They are both new substructure, and may be accretion debris of dwarf galaxies.

Keywords

stellar halo substructures gaia dr2 rave kinematics chemistry accretion debris

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@article{arxiv.2010.14281,
  title  = {Two substructures in the nearby stellar halo found in Gaia and RAVE},
  author = {Hefan Li and Cuihua Du and Yanbin Yang and Heidi Jo Newberg and Jun Ma and Jianrong Shi and Yunsong Piao},
  journal= {arXiv preprint arXiv:2010.14281},
  year   = {2020}
}

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8 pages, 9 figures, ApJ in press

Two substructures in the nearby stellar halo found in Gaia and RAVE

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