SIMBAD references

2022AJ....164...41W - Astron. J., 164, 41-41 (2022)

Influence of the Gaia-Sausage-Enceladus on the Density Shape of the Galactic Stellar Halo Revealed by Halo K Giants from the LAMOST Survey.

WU W., ZHAO G., XUE X.-X., PEI W. and YANG C.

Abstract (from CDS):

We present a study of the influence of the Gaia-Sausage-Enceladus (GSE) on the density shape of the Galactic stellar halo using 11,624 K giants from the LAMOST survey. Every star is assigned a probability of being a member of the GSE based on its spherical velocities and metallicity by a Gaussian mixture model. We divide the stellar halo into two parts by the obtained probabilities, of which one is composed of the GSE members and defined as the GSE-related halo, and the other one is referred to as the GSE-removed halo. Using a nonparametric method, the radial number density profiles of the two stellar halos can be well described by a single power law with a variable flattening q (r=sqrt( [****UnclosedBrace??****]R2 + [(Z/q(r))]2,ν= ν0r–α). The index α is 4.92 ± 0.12 for the GSE-related halo and 4.25 ± 0.14 for the GSE-removed halo. Both of the stellar halos are vertically flattened at smaller radii but become more spherical at larger radii. We find that the GSE-related halo is less vertically flattened than the GSE-removed halo, and the difference of q between the two stellar halos ranges from 0.07 to 0.15. However, after the consideration of the bias, it is thought to be within 0.08 at most of the radii. Finally, we compare our results with two Milky Way analogs that experience a significant major merger in the TNG50 simulation. The study of the two analogs also shows that the major merger-related stellar halo has a smaller ellipticity than the major merger-removed stellar halo.

Abstract Copyright: © 2022. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Milky Way stellar halo - Galaxy mergers - Milky Way formation - Milky Way Galaxy physics

Simbad objects: 2

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