相关论文: A Sagittarius-like simulated dwarf spheroidal gala…

We present a study of the central parts of the Sagittarius dwarf spheroidal galaxy (Sgr). We found a clear overdensity of Sgr's stars around M~54 (hereafter NS). NS is well represented by a King model and it has the characteristics of a…

Stellar streams are essential tracers of the gravitational potential of the Milky Way, with key implications to the problem of dark matter (DM) model distributions, either within or beyond phenomenological $\Lambda$CDM halos. For the first…

We study the shapes of Milky Way satellites in the context of the tidal stirring scenario for the formation of dwarf spheroidal galaxies. The standard procedures used to measure shapes involve smoothing and binning of data and thus may not…

The dwarf galaxies of the Local Group can be separated in three morphological groups: irregular, elliptical and spheroidal. As in the large galaxy clusters, there seems to be a morphology-position relationship: irregular galaxies are…

Metallicity gradients in the Sagittarius dwarf Galaxy (Sgr) are investigated by using infrared photometric data from the 2MASS survey. To search for metallicity effects, the giant branch in a field situated near the Center of the Sgr is…

Most dwarf spheroidal (dSph) satellites of the Milky Way follow exponential surface density profiles that decline sharply in the outer regions. The Sculptor (Scl) and Ursa Minor (UMi) dSphs deviate from this trend and show a clear excess of…

We present preliminary results of a long-term project to investigate the process of accretion and tidal disruption of dSph satellites in the Galactic halo and, in particular, to search for new tidal tails in a sample of nearby dSph…

We present metallicity and radial velocity for 450 bonafide members of the Sagittarius dwarf spheroidal (Sgr dSph) galaxy, measured from high resolution (R~18000) FLAMES@VLT spectra. The targets were carefully selected (a) to sample the…

We first review the results of the tidal stirring model for the transformation of gas-rich dwarf irregulars into dwarf spheroidals, which turns rotationally supported stellar systems into pressure supported ones. We emphasize the importance…

The time dependent tidal interaction of the Local Group Dwarf Spheroidal (dS) Galaxies with the Milky Way (MW) can fundamentally affect their dynamical properties. The model developed here extends earlier numerical descriptions of dS-MW…

Dwarf spheroidal galaxies (dSphs) appear to be some of the most dark matter dominated objects in the Universe. Their dynamical masses are commonly derived using the kinematics of stars under the assumption of equilibrium. However, these…

Standard cosmology predicts that dwarfs were the first galaxies to be formed in the Universe and that many of them merge afterwards to form bigger galaxies such as the Milky Way. This process would have left behind traces such as tidal…

Context. The Sagittarius (Sgr) dwarf spheroidal galaxy is currently being disrupted under the strain of the Milky Way. A reliable reconstruction of Sgr star formation history can only be obtained by combining core and stream information.…

We present comprehensive multi-component dynamical models of M54 (NGC6715), the nuclear star cluster of the Sagittarius dwarf galaxy (Sgr), which is undergoing a tidal disruption in the Milky Way halo. Previous papers in the series used a…

We present, for the first time, numerical simulations of young tidal dwarf galaxies (TDGs), including a self-consistent treatment of the tidal arm in which they are embedded. Thereby, we do not rely on idealised initial conditions, as the…

We outline the results of a study of the chemical composition of 14 stars in the Sagittarius dwarf spheroidal galaxy (Sgr dSph). For the Sgr dSph stars with [Fe/H]>-1 the abundances are highly unusual, showing a striking enhancement in…

Using collisionless N-body simulations of dwarf galaxies orbiting the Milky Way (MW) we construct realistic models of dwarf spheroidal (dSph) galaxies of the Local Group. The dwarfs are initially composed of stellar disks embedded in dark…

Two studies have recently reported the discovery of pronounced Halo substructure in the Sloan Digital Sky Survey (SDSS) commissioning data. Here we show that this Halo substructure is almost in its entirety due to the expected tidal stream…

How has the ``fluffy'' core of the Sgr dwarf galaxy survived multiple strong shocks from the tidal force of the Galactic halo and disc since the formation of the core a Hubble time ago? A scenario that Sgr was deflected to its current orbit…

This paper introduces new phase-space models of dwarf spheroidal galaxies (dSphs). The stellar component has an isotropic, lowered isothermal (or King) distribution function. A physical basis for the isotropization of stellar velocities is…