High energy astrophysics

Dirty fireballs are a hypothesized class of relativistic massive-star explosions with an initial Lorentz factor Γ$_init$ below the Γ$_init$ åisebox-0.5ex 100 required to produce a long-duration gamma-ray burst (LGRB), but which could still produce …

We present X-ray, UV, optical, and radio observations of the nearby (≈78 Mpc) tidal disruption event AT2021ehb/ZTF21aanxhjv during its first 430 days of evolution. AT2021ehb occurs in the nucleus of a galaxy hosting a≈10$^7$ M $_ødot$ black hole (M …