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 present the stellar density profile of the outer halo of the Galaxy tracedover a range of Galactocentric radii from $15< R_{GC} < 220$ kpc by bluehorizontal branch (BHB) stars. These stars are identified photometrically usingdeep $u-$band imaging from the new Canada-France-Imaging-Survey (CFIS) thatreaches 24.5 mag. This is combined with $griz$ bands from Pan-STARRS 1 andcovers a total of $\sim4000$ deg$^2$ of the northern sky. We present a newmethod to select BHB stars that has low contamination from blue stragglers andhigh completeness. We use this sample to measure and parameterize the threedimensional density profile of the outer stellar halo. We fit the profile using(i) a simple power-law with a constant flattening (ii) a flattening that variesas a function of Galactocentric radius (iii) a broken power law profile. Wefind that outer stellar halo traced by the BHB is well modelled by a brokenpower law with a constant flattening of $q=0.86 \pm 0.02$, with an inner slopeof $\gamma=4.24 \pm 0.08$. This is much steeper than the preferred outerprofile that has a slope of $\beta=3.21\pm 0.07$ after a break radius of$r_b=41.4^{+2.5}_{-2.4}$ kpc. The outer profile of the stellar halo trace byBHB stars is shallower than that recently measured using RR Lyrae, a surprisingresult given the broad similarity of the ages of these stellar populations.

A-type stars in the Canada-France Imaging Survey I. The stellar halo of the Milky Way traced to large radius by blue horizontal branch stars