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

We measure the intrinsic shapes and alignments of the dwarf spheroidal (dSph)galaxies of the Local Group. We find the dSphs of the Milky Way areintrinsically flatter (mean intrinsic ellipticity $\mu_E\sim0.6$) than those ofM31 ($\mu_E\sim0.5$) and that the classical Milky Way dSphs($M_V<-8.5\,\mathrm{mag}$) are rounder ($\mu_E\sim0.5$) than the ultrafaints($\mu_E\sim0.65$) whilst in M31 the shapes of the classical and ultrafaintdSphs are very similar. The M31 dSphs are preferentially radially aligned witha dispersion of $\sim45\deg$. This signal is driven by the ultrafaintpopulation whilst the classical M31 dSphs are consistent with a randomorientation. We compare our results to the Aquarius mock stellar catalogues ofLowing et al. and find the subhalo radial alignment distribution matches theLocal Group dSphs results, whilst the Aquarius intrinsic ellipticities aresignificantly smaller than the data ($\Delta\langle E\rangle\approx0.4$). Weprovide evidence that the major axes of the Milky Way satellites lie within apreferential plane with normal vector pointing towards $(\ell,b)=(127,5)\deg$.We associate this preferred direction with the Vast Polar Orbital structurealthough their respective great circles are offset by $\sim30\deg$. No signalin the alignments of the major axes is found in M31, suggesting that the GreatPlane of Satellites is formed from recent accretion or chance alignment.Finally, we provide predictions for the discrepancy between the velocitydispersion versus scale radius distributions for the Milky Way and M31populations and demonstrate that the projection effect from viewing similarpopulations from two different locations does not account for the discrepancywhich is probably caused by increased tidal disruption in M31.

The shapes and alignments of the satellites of the Milky Way and Andromeda