A nearby black hole is secretly 100 times more powerful than we thought, solving a massive energy mystery in our galaxy.
arXiv · March 18, 2026 · 2603.16714
The Takeaway
New simulations of the black hole V4641 Sgr show it is pumping out ultra-high-energy radiation that was thought to be impossible given its dim appearance. The discovery proves the black hole is a much more intense cosmic engine than anyone realized, hidden behind a dense shroud of gas.
From the abstract
Recent observations by LHAASO and HAWC have revealed extended ultrahigh-energy (UHE; $E>100$ TeV) gamma-ray emission assoicated to the black-hole X-ray binary (BHXRB) V4641 Sgr, with a spectrum extending up to $\sim0.8$ PeV. Interpreting this emission requires a very {high time-averaged non-thermal particle power}, significantly exceeding the long-term observed X-ray luminosity which is commonly used as a proxy for the accretion power, leading to an apparent ``energy crisis''. To address this, w