Speaker
Description
Ultraluminous X-ray sources (ULXs) represent the most extreme accreting X-ray binaries in the local Universe, with luminosities up to $ \sim10^{41}\ \rm erg/s$. They are now widely interpreted as stellar-mass compact objects accreting at super-Eddington rates in majority, as indicated by their soft X-ray spectral components, coherent pulsations in multiple systems, and the presence of powerful, mildly relativistic winds.
In this talk, I will outline the breakthrough science that will become possible with next-generation high-resolution X-ray spectrometers. Since accretion onto compact objects is broadly scale-invariant with mass, ULXs provide a unique laboratory for understanding disc structure, wind launching, and radiative feedback—processes that also shape stellar-mass X-ray binaries, tidal disruption events, and the supermassive black-holes in the early phases of the Universe.
NewAthena/X-IFU, with $\sim$ 4 eV resolution and $\gtrsim$ 6000 $\rm cm^{2}$ effective area, will make possible to detect and disentangle complex outflow geometries, separating ultrafast outflow from slower wind phases. Crucially, it will enable for the first time measurements on sub-hour timescales, allowing us to follow the coupled evolution of the disc and winds and to discriminate between radiative/thermal driving and magnetic acceleration.
This topic will be the core of the paper whose draft I submitted and has just been approved for the NewAthena special issue on JHEAP.
