Bibcode
Iorio, G.; Nipoti, C.; Battaglia, G.; Sollima, A.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 4, p.5692-5710
Fecha de publicación:
8
2019
Número de citas
18
Número de citas referidas
16
Descripción
Dwarf spheroidal galaxies (dSphs) appear to be some of the most dark
matter (DM)-dominated objects in the Universe. Their dynamical masses
are commonly derived using the kinematics of stars under the assumption
of equilibrium. However, these objects are satellites of massive
galaxies (e.g. the Milky Way) and thus can be influenced by their tidal
fields. We investigate the implication of the assumption of equilibrium
focusing on the Sculptor dSph by means of ad hoc N-body simulations
tuned to reproduce the observed properties of Sculptor following the
evolution along some observationally motivated orbits in the Milky Way
gravitational field. For this purpose, we used state-of-the-art
spectroscopic and photometric samples of Sculptor's stars. We found that
the stellar component of the simulated object is not directly influenced
by the tidal field, while {≈ } 30 - 60{{ per cent}} of the mass of
the more diffuse DM halo is stripped. We conclude that, considering the
most recent estimate of the Sculptor proper motion, the system is not
affected by the tides and the stellar kinematics represents a robust
tracer of the internal dynamics. In the simulations that match the
observed properties of Sculptor, the present-day dark-to-luminous mass
ratio is ≈6 within the stellar half-light radius (≈0.3 kpc) and
>50 within the maximum radius of the analysed data set
(≈1.5°, ≈2 kpc).
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Matteo
Monelli