NBIA Astroparticle Seminar: Alejandro Vigna-Gómez

(Max Planck Institute for Astrophysics)

Black-hole binaries in the Local Group

For over five decades, Galactic X-ray source Cygnus X-1 has been the archetype for high-mass X-ray binaries (HMXBs). HMXBs are a particular configuration of black-hole (BH) binary where an O-type star slowly feeds a compact object which forms an X-ray-emitting accretion disk. Recently, the report of VFTS 243 became the first detection of an X-ray-quiet BH binary in the vicinities of the Milky Way. In this talk, I discuss the formation pathway of VFTS 243 and its implications for supernova theory; in particular, as it pertains to asymmetries during collapse and to natal kicks. Moreover, I put VFTS 243 in the context of other BH binaries in the Local Group and highlight how X-ray-quiescent binaries complement the population of BH binaries detected via X-rays and ground-based gravitational-wave observatories.