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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We present the first results from the X-SHOOTER Lyman-$\alpha$ survey at$z=2$ (XLS-$z2$). XLS-$z2$ is a deep spectroscopic survey of 35 Lyman-$\alpha$emitters (LAEs) utilising $\approx90$ hours of exposure time with VLT/X-SHOOTERand covers rest-frame Ly$\alpha$ to H$\alpha$ emission with R$\approx4000$. Wepresent the sample selection, the observations and the data reduction. Systemicredshifts are measured from rest-frame optical lines for 33/35 sources. In thestacked spectrum, our LAEs are characterised by an interstellar medium withlittle dust, a low metallicity and a high ionisation state. The ionisingsources are young hot stars that power strong emission-lines in the optical andhigh ionisation lines in the UV. The LAEs exhibit clumpy UV morphologies andhave outflowing kinematics with blue-shifted SiII absorption, a broad [OIII]component and a red-skewed Ly$\alpha$ line. Typically 30 % of the Ly$\alpha$photons escape, of which one quarter on the blue side of the systemic velocity.A fraction of Ly$\alpha$ photons escapes directly at the systemic suggestingclear channels enabling a $\approx10$ % escape of ionising photons, consistentwith an inference based on MgII. A combination of a low effective HI columndensity, a low dust content and young star-burst determine whether a starforming galaxy is observed as a LAE. The first is possibly related to outflowsand/or a fortunate viewing angle, while we find that the latter two in LAEs aretypical for their stellar mass of 10$^9$ M$_{\odot}$.

The X-SHOOTER Lyman-$\alpha$ survey at z=2 (XLS-z2) I: What makes a galaxy a Lyman-$\alpha$ emitter?