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

Satellite galaxies within the Milky Way's (MW) virial radius$R_{\mathrm{vir}}$ are typically devoid of cold gas due to ram pressurestripping by the MW's corona. The density of this corona is poorly constrainedtoday and essentially unconstrained in the past, but can be estimated using rampressure stripping. In this paper, we probe the MW corona at $z\approx 1.6$using the Draco dwarf spheroidal galaxy. We assume that i) Draco's orbit isdetermined by its interaction with the MW, whose dark matter halo we evolve intime following cosmologically-motivated prescriptions, ii) Draco's starformation was quenched by ram pressure stripping and iii) the MW's corona isapproximately smooth, spherical and in hydrostatic equilibrium. We used GAIAproper motions to set the initial conditions and Draco's star formation historyto estimate its past gas content. We found indications that Draco was strippedof its gas during the first pericentric passage. Using 3D hydrodynamicalsimulations at a resolution that enables us to resolve individual supernovaeand assuming no tidal stripping, which we estimate to be a minor effect, wefind a density of the MW corona $\geq 8\times 10^{-4}$ cm$^{-3}$ at a radius$\approx 0.72R_{\mathrm{vir}}$. This provides evidence that the MW's corona wasalready in place at $z\approx 1.6$ and with a higher density than today. Ifisothermal, this corona would have contained all the baryons expected by thecosmological baryon fraction. Extrapolating to today shows good agreement withliterature constraints if feedback has removed $\lesssim 30$% of baryonsaccreted onto the halo.

The density of the Milky Way's corona at $z\approx 1.6$ through ram pressure stripping of the Draco dSph galaxy