Astrophysics Colloquium

Supermassive black hole binaries (SMBHBs) should be common in galactic nuclei as a result of frequent galaxy mergers. Yet they remain undetectable, especially during the final stage of their evolution. At this stage, SMBHBs are expected to emit...

The origin of extraterrestrial energetic particles ("cosmic rays") has puzzled scientists since the pioneering discovery by Victor Hess in 1912. In the last decade, however, modern supercomputers and multi-wavelength observations have opened new...