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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We have examined the resolved stellar populations at large galactocentricdistances along the minor axis (from 10 kpc up to between 40 and 75 kpc), withlimited major axis coverage, of six nearby highly-inclined Milky Way-mass discgalaxies using HST data from the GHOSTS survey. We select red giant branchstars to derive stellar halo density profiles. The projected minor axis densityprofiles can be approximated by power laws with projected slopes of between$-2$ and $-3.7$ and a diversity of stellar halo masses of $1-6\times10^{9}M_{\odot}$, or $2-14\%$ of the total galaxy stellar masses. The typicalintrinsic scatter around a smooth power law fit is $0.05-0.1$ dex owing tosubstructure. By comparing the minor and major axis profiles, we inferprojected axis ratios $c/a$ at $\sim 25$ kpc between $0.4-0.75$. The GHOSTSstellar haloes are diverse, lying between the extremes charted out by the(rather atypical) haloes of the Milky Way and M31. We find a strong correlationbetween the stellar halo metallicities and the stellar halo masses. We compareour results with cosmological models, finding good agreement between ourobservations and accretion-only models where the stellar haloes are formed bythe disruption of dwarf satellites. In particular, the strong observedcorrelation between stellar halo metallicity and mass is naturally reproduced.Low-resolution hydrodynamical models have unrealistically high stellar halomasses. Current high-resolution hydrodynamical models appear to predict stellarhalo masses somewhat higher than observed but with reasonable metallicities,metallicity gradients and density profiles.

Diverse Stellar Haloes in Nearby Milky Way-Mass Disc Galaxies