Exploring ultra-fast outflows in active galactic nuclei with NewAthena 

Dr. Yerong Xu

Institut de Ciències de l'Espai (CSIC)

At the heart of most galaxies lie supermassive black holes (SMBHs), millions to billions of times the mass of the Sun. Although tiny compared to their host galaxies, they appear to manage to shape the evolution of galaxies. But how can an object influence an entire galaxy that is billions of times larger?

An answer may be found in powerful winds called ultra-fast outflows (UFOs). These streams of gas are launched from the nearby regions of the black hole at speeds reaching up to 40% of the speed of light. Unlike, radio jets that shoot into intergalactic space, UFOs spread over wide angles. This allows them to deposit enormous amounts of energy and matter directly into the host galaxy, heating gas and regulating the fuel available for both black hole growth and star formation. They considered a key part of “black hole feedback,” the process that links the growth of black holes and galaxies.

Despite their importance, many mysteries remain. What mechanism launches these winds, intense radiation pressure or magnetic forces? How efficiently do they transfer energy into the galaxy?

Current X-ray observatories have collected numerous examples of UFOs; however, studying this fundamental question is complex and requires the highest-quality data. The upcoming ESA mission NewAthena will change the game. In particular, its X-ray Integral Field Unit (X-IFU), combining a large collecting area with unprecedented spectral resolution, will deliver, for the first time, sharp X-ray spectra that will allow us to precisely measure the speed, density, and ionisation state of UFOs. Moreover, NewAthena will detect UFOs in fainter,more distant galaxies, revealing how they impact the evolution of galaxies.