• Black hole plasma jets are formed when the accretion disk around the black hole abruptly contracts, triggering the eruption of a plasma jet.
• NASA's IXPE confirms that X-rays in blazar jets are generated by interactions between fast-moving electrons and photons.
• Understanding these jet mechanisms offers new perspectives on galaxy evolution and black hole physics and can potentially be applied to supermassive black holes.

Recent research has advanced our understanding of black hole jets, powerful streams of matter and energy ejected from the vicinity of black holes. One study, focusing on stellar black holes, reveals that jet formation is linked to the dynamic contraction of the accretion disk surrounding the black hole. A separate study, using NASA's IXPE, clarifies how X-rays are generated within the jets of blazars, demonstrating that electrons interacting with photons through Compton scattering are the primary source.

• What: Plasma jets are ejected from black holes due to accretion disk dynamics and particle interactions. X-rays are generated within these jets through Compton scattering.
• Who: Kazutaka Yamaoka (Nagoya University), Iván Agudo (Instituto de Astrofísica de Andalucía – CSIC), Ioannis Liodakis (Institute of Astrophysics – FORTH), Steven Ehlert (Marshall Space Flight Center), Enrico Costa (Istituto di Astrofísica e Planetologia Spaziali)
• When: IXPE observed BL Lac at the end of November 2023 for seven days. The Japanese study was recently published in Publications of the Astronomical Society of Japan.
• Where: Observations were made of stellar black holes and the blazar BL Lacertae.

The two articles complement each other by exploring different aspects of black hole jets. The Techno-Science.net article focuses on the mechanism of jet formation related to the accretion disk around stellar black holes, while the NASA article elucidates the process of X-ray generation within blazar jets using IXPE data. The NASA article's finding that electrons interacting with photons cause X-ray emissions refines earlier hypotheses and provides a clearer understanding of the jet's composition and energy transfer. The consistency between the studies strengthens the understanding of the dynamics of black hole phenomena.

This was one of the biggest mysteries about supermassive black hole jets, and IXPE, with the help of a number of supporting ground-based telescopes, finally provided us with the tools to solve it.

The fact that optical polarization was so much higher than in the X-rays can only be explained by Compton scattering.

IXPE’s polarized X-ray vision has solved several long lasting mysteries, and this is one of the most important. In some other cases, IXPE results have challenged consolidated opinions and opened new enigmas, but this is how science works and, for sure, IXPE is doing very good science.

These new findings significantly advance the understanding of black hole jets, clarifying their formation mechanisms and X-ray emission processes, particularly the role of electron-photon interactions via Compton scattering. The studies emphasize the importance of dynamic conditions and turbulence within the accretion disk, revealing that electrons, rather than protons, are responsible for X-ray generation. Future research will focus on extending these findings to supermassive black holes and exploring the variability of blazars, with specific attention to rapid flux and polarization changes, and microvariability. This includes investigating the newly discovered phenomenon of particle acceleration during the quiescent phases of black holes and further exploration of the differences between X-ray and radio wave observations to understand jet dynamics and knot formations. These efforts promise deeper insights into the complex interplay between magnetic fields, particle acceleration, and radiative processes in these extreme cosmic environments.