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

We use observations from the ACS study of Galactic globular clusters toinvestigate the spatial distribution of the inner regions of the disruptingSagittarius dwarf spheroidal galaxy (Sgr). We combine previously publishedanalyses of four Sgr member clusters located near or in the Sgr core (M54, Arp2, Terzan 7 and Terzan 8) with a new analysis of diffuse Sgr materialidentified in the background of five low-latitude Galactic bulge clusters (NGC6624, 6637, 6652, 6681 and 6809) observed as part of the ACS survey. Bycomparing the bulge cluster CMDs to our previous analysis of the M54/Sgr core,we estimate distances to these background features. The combined data from fourSgr member clusters and five Sgr background features provides nine independentmeasures of the Sgr distance and, as a group, provide uniformly measured andcalibrated probes of different parts of the inner regions of Sgr spanningtwenty degrees over the face of the disrupting dwarf. This allows us, for thefirst time, to constrain the three dimensional orientation of Sgr's disruptingcore and globular cluster system and compare that orientation to thepredictions of an N-body model of tidal disruption. The density and distance ofSgr debris is consistent with models that favor a relatively high Sgr core massand a slightly greater distance (28-30 kpc, with a mean of 29.4 kpc). Ouranalysis also suggests that M54 is in the foreground of Sgr by ~2 kpc,projected on the center of the Sgr dSph. While this would imply a remarkablealignment of the cluster and the Sgr nucleus along the line of sight, we cannot identify any systematic effect in our analysis that would falsely createthe measured 2 kpc separation. Finally, we find that the cluster Terzan 7 hasthe most discrepant distance (25 kpc) among the four Sgr core clusters, whichmay suggest a different dynamical history than the other Sgr core clusters.

astrophysical journal/the astrophysical journal

The ACS Survey of Galactic Globular Clusters XI: The Three-Dimensional  Orientation of the Sagittarius Dwarf Spheroidal Galaxy and its Globular  Clusters