2019MNRAS.484.4471F


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.20CET19:31:09

2019MNRAS.484.4471F - Mon. Not. R. Astron. Soc., 484, 4471-4483 (2019/April-3)

The origin of galactic metal-rich stellar halo components with highly eccentric orbits.

FATTAHI A., BELOKUROV V., DEASON A.J., FRENK C.S., GOMEZ F.A., GRAND R.J.J., MARINACCI F., PAKMOR R. and SPRINGEL V.

Abstract (from CDS):

Using the astrometry from the ESA's Gaia mission, previous works have shown that the Milky Way stellar halo is dominated by metal-rich stars on highly eccentric orbits. To shed light on the nature of this prominent halo component, we have analysed 28 Galaxy analogues in the Auriga suite of cosmological hydrodynamics zoom-in simulations. Some three quarters of the Auriga galaxies contain prominent components with high radial velocity anisotropy, β > 0.6. However, only in one third of the hosts do the high-β stars contribute significantly to the accreted stellar halo overall, similar to what is observed in the Milky Way. For this particular subset we reveal the origin of the dominant stellar halo component with high metallicity, [Fe/H] ∼ -1, and high orbital anisotropy, β > 0.8, by tracing their stars back to the epoch of accretion. It appears that, typically, these stars come from a single dwarf galaxy with a stellar mass of the order of 109–1010^ M_☉that merged around 6-10 Gyr ago, causing a sharp increase in the halo mass. Our study therefore establishes a firm link between the excess of radially anisotropic stellar debris in the halo and an ancient head-on collision between the young Milky Way and a massive dwarf galaxy.

Abstract Copyright: © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): methods: numerical, obsevational - Galaxy: evolution - Galaxy: halo - Galaxy: kinematics and dynamics

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME Sgr Stream St* 02 22 +00.0           ~ 617 0
2 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14352 1
3 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11052 0
4 NAME SDG G 18 55 03.1 -30 28 42   4.5 3.6     ~ 1651 2
5 NAME Her-Aql Cloud Cld 19 04 +06.3           ~ 86 0
6 NAME Virgo Stellar Stream MGr ~ ~           ~ 96 0

    Equat.    Gal    SGal    Ecl

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2019.11.20-19:31:09

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