Landing page for project EY049

Stellar-mass black hole and neutron star binaries can show apparent X-ray luminosities significantly above their Eddington luminosities along their optically thin X-ray funnels. These are referred as ultraluminous X-ray sources (ULXs). Recently, the high-mass X-ray binary Cyg X-3 has been identified as such a rarely-seen object with a jet propagating along and within the X-ray funnel. Previous ULX simulations show that the jet and the X-ray funnel have a similar opening angle. To probe the ULX scenario, we propose to observe Cyg X-3 for 6 hours with the EVN at 22 GHz. The deep VLBI observations allow us to accurately characterize the jet parameters, particularly the jet opening angle. With these inputs, we could provide evidence for a strong coupling between the jet and the X-ray funnel and accurately constrain the geometric beaming effect and the intrinsic luminosity in Cyg X-3. If accretion onto a compact object is a scale-free process, this VLBI method would help to probe possible X-ray funnels and complex engines in the more distant super-Eddington accretion systems from ULXs to AGNs.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197