相关论文: Dark halo structure in the Carina dwarf spheroidal…
The evolution of small systems such as dwarf spheroidal galaxies (dSph) is likely to have been a balance between external environmental effects and internal processes within their own relatively shallow potential wells. Assessing how strong…
Recent observations suggest that Carina and other nearby dwarf spheroidal galaxies are surrounded by unbound stars tidally stripped by the Milky Way. We run high-resolution N-Body simulations of dwarf galaxies orbiting within the Milky Way…
We investigate the non-spherical density structure of dark halos of the dwarf spheroidal (dSph) galaxies in the Milky Way and Andromeda galaxies based on revised axisymmetric mass models from our previous work. The models we adopt here…
By fitting a flexible stellar anisotropy model to the observed surface brightness and line-of-sight velocity dispersion profiles of Draco we derive a sequence of cosmologically plausible two-component (stars + dark matter) models for this…
The detailed abundances of 23 elements in nine bright RGB stars in the Carina dSph are presented based on high resolution spectra gathered at the VLT and Magellan telescopes. A spherical model atmospheres analysis is applied using standard…
We report on the first in a series of studies of the Carina dwarf spheroidal galaxy, a nearby satellite of our Galaxy. Our two major results are: 1) precise BI photometry ($\sigma_{B-I} \simlt 0.05$ for $V \simlt 22$) for 11,489 stars in…
We present deep optical photometry from the DECam imager on the 4m Blanco telescope of over 12 deg$^2$ around the Carina dwarf spheroidal, with complete coverage out to 1 degree and partial coverage extending out to 2.6 degrees. Using a…
As part of our survey for substructure in the Milky Way halo as traced by giant stars, and to look for tidal stellar debris in the halo viable for measurement of the Galactic mass potential with SIM, we explore the distribution of stars…
Dark matter only simulations of galaxy formation predict many more subhalos around a Milky Way like galaxy than the number of observed satellites. Proposed solutions require the satellites to inhabit dark matter halos with masses between…
We report the results of N-body simulations of disrupting satellites aimed at exploring whether the observed features of dSphs can be accounted for with simple, mass-follows-light (MFL) models including tidal disruption. As a test case, we…
We present a new study of the evolution of the Carina dwarf galaxy that includes a simultaneous derivation of its orbit and star formation history. The structure of the galaxy is constrained through orbital parameters derived from the…
We present the spatially resolved star formation history (SFH) of the Carina dwarf spheroidal galaxy, obtained from deep, wide-field g,r imaging and a metallicity distribution from the literature. Our photometry covers $\sim2$ deg$^2$,…
We investigate the color-magnitude diagram (CMD) of the Carina dwarf spheroidal galaxy using data of Stetson et al. (2011) and synthetic CMDs based on isochrones of Dotter et al. (2008), in terms of the parameters [Fe/H], age, and…
A new large-area Washington M,T_2+DDO51 filter survey of more than 10 deg^2 around the Carina dSph galaxy reveals a spectroscopically confirmed power law radial density "break" population of Carina giant stars extending several degrees…
We examine the dynamics of stellar systems embedded within cold dark matter (CDM) halos in order to assess observational constraints on the dark matter content of Local Group dwarf spheroidals (dSphs). Our analysis shows that the total mass…
We use analytical and N-body methods to examine the survival of wide stellar binaries against repeated encounters with dark substructures orbiting in the dark matter haloes of dwarf spheroidal galaxies (dSphs). Our models adopt…
The dwarf spheroidal (dSph) satellites of the Local Group have long been thought to be simple spheroids of stars embedded within extended dark matter halos. Recently, however, evidence for the presence of spatially and kinematically…
The question of the existence of active tidal disruption around various dSph galaxies remains controversial. That debate often centers on the nature (bound vs. unbound) of extended populations of stars. However, the more fundamental issue…
Previous studies of the Carina region have revealed its complexity and richness as well as a significant number of early-type stars. In many cases, these studies only concentrated on the central region or were not homogeneous. This latter…
The structure and dark matter halo core properties of dwarf spheroidal galaxies (dSphs) are investigated. A double-isothermal model of an isothermal stellar system, embedded in an isothermal dark halo core provides an excellent fit to the…