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

Compact Galactic binary systems with orbital periods of a few hours areexpected to be detected in gravitational waves (GW) by LISA or a similarmission. At present, these so-called verification binaries provide predictionsfor GW frequency and amplitude. A full polarisation prediction would provide anew method to calibrate LISA and other GW observatories, but requires resolvingthe orientation of the binary on the sky, which is not currently possible. Wesuggest a method to determine the elusive binary orientation and hence predictthe GW polarisation, using km-scale optical intensity interferometry. The mostpromising candidate is CD-30$^{\circ}$ 11223, consisting of a hot heliumsubdwarf with $m_B = 12$ and a much fainter white dwarf companion, in a nearlyedge-on orbit with period 70.5 min. We estimate that the brighter star istidally stretched by 6%. Resolving the tidal stretching would provide thebinary orientation. The resolution needed is far beyond any current instrument,but not beyond current technology. We consider scenarios where an array oftelescopes with km-scale baselines and/or the Very Large Telescope (VLT) andExtremely Large Telescope (ELT) are equipped with recently-developed kilo-pixelsub-ns single-photon counters and used for intensity interferometry. Weestimate that a team-up of the VLT and ELT could measure the orientation to$\pm 1^{\circ}$ at 2$\sigma$ confidence in 24 hours of observation.

Towards a Polarisation Prediction for LISA via Intensity Interferometry