W.‐R. Hamann

JWST Reveals a Highly Ionized Nebula Powered by an Ultraluminous X-Ray Source with a Massive Black Hole in the Metal-poor Galaxy Holmberg II

Abstract Recent James Webb Space Telescope (JWST) observations have revealed fine-structure lines of ions with ionization potentials ≳50 eV, such as [Ne v ] and [O iv ], in nebular spectra of some low-metallicity galaxies, raising questions about the nature of the ionizing source...