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

In recent years, accurate observational constraints become available for anincreasing number of Galactic X-ray binaries. Together with proper motionmeasurements, we could reconstruct the full evolutionary history of X-raybinaries back to the time of compact object formation. In this paper, wepresent the first study of the persistent X-ray source Cygnus\;X-1 that takesinto account of all available observational constraints. Our analysis accountsfor three evolutionary phases: orbital evolution and motion through theGalactic potential after the formation of black hole (BH), and binary orbitaldynamics at the time of core collapse. We find that the mass of the BHimmediate progenitor is $15.0 - 20.0$ M$_\sun$, and at the time of corecollapse, the BH has potentially received a small kick velocity of $\le 77$ kms$^{-1}$ at 95% confidence. If the BH progenitor mass is less than $\sim 17$M$_\sun$, a non zero natal kick velocity is required to explain the currentlyobserved properties of Cygnus\;X-1. Since the BH has only accreted mass fromits companion's stellar wind, the negligible amount of accreted mass isimpossible to explain the observationally inferred BH spin of $a_* > 0.95$, andthe origin of this extreme BH spin must be connected to the BH formationitself. Right after the BH formation, we find that the BH companion is a $19.8- 22.6$ M$_\sun$ main sequence star, orbiting the BH at a period of $4.7 - 5.2$days. Furthermore, recent observations show that the BH companion is currentlysuper-synchronized. This super-synchronism indicates that the strength of tidesexerted on the BH companion should be weaker by a factor of at least twocompared to the usually adopted strength.

Understanding Compact Object Formation and Natal Kicks. III. The case of Cygnus X-1