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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Our GHOSTS survey measures the stellar envelope properties of 14 nearby diskgalaxies by imaging their resolved stellar populations with HST/ACS&WFPC2. Mostof the massive galaxies in the sample (Vrot >200 km/s) have very extendedstellar envelopes with Sersic law profiles or mu(r)~r^-2.5 power law profilesin the outer regions. For these massive galaxies we can fit the central bulgelight and the outer halo out to 30 kpc with one and the same Sersic profile andthe stellar surface density of the profiles correlate with Hubble type andbulge- to-disk ratio. This suggests that the central bulges and inner halos arecreated in the same process. Smaller galaxies (Vrot ~100 km/s) have muchsmaller stellar envelopes, but depending on geometry, they could still be moreluminous than expected from satellite remnants in hierarchical galaxy formationmodels. Alternatively, they could be created by disk heating through thebombardment of small dark matter sub-halos. The halos we fit are highlyflattened, with minor- over-ma jor axis ratios c/a=0.6. The halos are somewhatmore compact than hierarchical model predictions. The halos show smallmetallicity gradient out to 30 kpc and the massive galaxies have typical[Fe/H]~-0.8. We find indications of halo substructure in many galaxies, butsome halos seem remarkable smooth.

GHOSTS - Bulges, Halos, and the Resolved Stellar Outskirts of Massive Disk Galaxies