English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Using collisionless N-body simulations of dwarf galaxies orbiting the MilkyWay (MW) we construct realistic models of dwarf spheroidal (dSph) galaxies ofthe Local Group. The dwarfs are initially composed of stellar disks embedded indark matter haloes with different inner density slopes and are placed on aneccentric orbit typical for MW subhaloes. After a few Gyr of evolution thestellar component is triaxial as a result of bar instability induced by tidalforces. Observing the simulated dwarfs along three principal axes of thestellar component we create mock data sets and determine the their half-lightradii and line-of-sight velocity dispersions. Using the estimator proposed byWolf et al. we calculate masses within half-light radii. The masses obtainedthis way are over(under)estimated by up to a factor of two when the line ofsight is along the longest (shortest) axis of the stellar component. We thendivide the initial stellar distribution into an inner and outer population andtrace their evolution in time. The two populations, although affected by tidalforces, retain different density profiles even after a few Gyr. We measure thehalf-light radii and velocity dispersions of the stars in the two populationsalong different lines of sight and use them to estimate the slope of the massdistribution in the dwarfs following the method proposed by Walker &Penarrubia. The inferred slopes are systematically over- or underestimated,depending on the line of sight. In particular, when the dwarf is seen along thelongest axis of the stellar component, a significantly shallower densityprofile is inferred than the real one measured from the simulations. Since mostdSphs are non-spherical and their orientation with respect to our line of sightis unknown, the method can be reliably applied only to a large sample of dwarfswhen these systematic errors are expected to be diminished.

Can we measure the slopes of density profiles in dwarf spheroidal galaxies?