Detached high-mass X-ray binaries : mass transfer and coupling to the magnetosphere

par Ileyk El Mellah (UGA)

jeudi 24 juin 2021, 11:00 → 12:00 Europe/Paris

Auditorium & Zoom (LAPTh)

Once massive stars leave the main sequence, their evolution is largely set by mass loss through intense radiation-driven winds. Stellar multiplicity has been recognized as a ubiquitous feature: stars seldom live an effectively single life. In the advanced evolutionary stages of a massive binary, mass transfer via stellar winds can become significant and decide the final fate of both bodies. In high mass X-ray binaries (HMXBs), which are good progenitor candidates for merging compact objects, a blue supergiant is in close orbit with a a young and highly magnetized neutron star (NS) or a black hole (BH) which captures a fraction of the stellar wind.

In this talk, I will show how the numerical tool grants us access to accurate estimates of the mass and angular momentum transfer rates in wind-fed HMXBs. After describing the conditions of formation of wind-captured disks around the NS or the BH, I will discuss the long term evolution of the orbital separation. We will see that HMXBs in the solar neighbourhood spend a significant fraction of their lifetime with an X-ray luminosity above detectable levels. I will present the implications for phases of enhanced mass transfer, for the spinning up and down of the accretor and for the natal kick of the compact object. Finally, I will report on recent results concerning particle acceleration in the magnetosphere of a Kerr BH connected to a Keplerian disk, a mechanism which might be responsible for coronal heating and non-thermal flares.

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After a seminal research experience with Saul Rappaport at MIT in 2011-2012, I graduated in Paris in 2016. During my PhD, I made use of grid-based numerical simulations to characterize the flow surrounding an accreting compact object moving with respect to an ambient medium. In Leuven, I was granted a Pegasus Marie Curie fellowship to model mass transfer through wind capture in high-mass X-ray binaries. I moved to Grenoble in October this year where I now work with Benoît Cerutti on particle-in-cell simulations of magnetic reconnection in the magnetosphere of black holes.