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 use Chandra and XMM observations of the globular clusters $\omega$ Cen andNGC 6397 to measure the spectrum of their quiescent neutron stars (NSs), andthus to constrain the allowed ranges of mass and radius for each. We also useHubble Space Telescope photometry of NGC 6397 to identify a potential opticalcompanion to the quiescent NS, and find evidence that the companion lackshydrogen. We carefully consider a number of systematic problems, and show thatthe choices of atmospheric composition, interstellar medium abundances, andcluster distances can have important effects on the inferred NS mass andradius. We find that for typical NS masses, the radii of both NSs areconsistent with the 10-13 km range favored by recent nuclear physicsexperiments. This removes the evidence suggested by Guillot and collaboratorsfor an unusually small NS radius, which relied upon the small inferred radiusof the NGC 6397 NS.

Improved Mass and Radius Constraints for Quiescent Neutron Stars in Omega Cen and NGC 6397