When a black hole’s jets turn off, they collapse like bubbles and basically camouflage the black hole so we can't find it.
arXiv · March 13, 2026 · 2603.11361
Why it matters
Active black holes blow massive radio lobes into space, but astronomers see far fewer 'dead' ones than models predict. This research reveals that in dense galaxy clusters, these lobes are so unstable that once the black hole stops feeding, they are crushed by surrounding pressure in just a few million years, making the black hole look like it was never active.
From the abstract
We propose that an observed scarcity of remnant lobed AGNs in dense clusters results from a peculiarity in their dynamics upon the cessation of jet activity: a rapid `implosion' of lobes that, in their active phase, were primarily supported by the momentum flux of the jet. We investigate this behaviour by analysing the asymptotic behaviour of the RAiSE dynamical model and comparing our predictions both to the full model and hydrodynamic simulations. We find that remnant lobes powered by weak jet