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 observed the Galactic black hole X-ray binary V4641 Sgr with the highresolution transmission gratings on Chandra during the source's 2020 outburst.Over two epochs of Chandra gratings observations, we see numerous highlyionized metal lines, superimposed on a hot, disc-dominated X-ray continuum. Themeasured inner disc temperatures and luminosities imply an unfeasibly smallinner disc radius, such that we suggest that the central engine of V4641 Sgr isobscured, and we are viewing scattered X-rays. We find that the emission linesin the Chandra spectra cannot be constrained by a single photoionized model,instead finding that two separate photoionized model components are required,one to reproduce the iron lines and a second for the other metals. We comparethe observed X-ray spectra of V4641 Sgr to optical studies during previousoutbursts of the source, suggesting that the lines originate in an accretiondisc wind, potentially with a spherical geometry.

High resolution X-ray spectroscopy of V4641 Sgr during its 2020 outburst