The brightest high-energy light from a famous black hole system actually comes from the 'backwards' jet pointing away from Earth.
March 31, 2026
Original Paper
The counterjet dominates the production of PeV photons from Cyg X-3
arXiv · 2603.27805
The Takeaway
Usually, we see the most light from jets pointing toward us due to a searchlight-like effect called beaming. In this system, the jet pointing away (the counterjet) has a clearer path to smash into nearby gas, creating a massive 'glow' that outshines the jet facing us.
From the abstract
We study the physical mechanisms underlying the production of orbitally-modulated PeV photons from Cyg X-3, recently discovered by the LHAASO collaboration. Our key findings are as follows. Helium nuclei are accelerated in a compact and strongly magnetized region within the jet, but they then quickly advect downstream to regions with a weaker field, allowing them to diffuse out of the jet, where they produce pions in hadronic collisions with both the stellar photons and the stellar wind of the W