Kavli Affiliate: Claudio Ricci | First 5 Authors: Jeffrey D. McKaig, Shobita Satyapal, Ari Laor, Nicholas P. Abel, Sara M. Doan | Summary: Forbidden collisionally excited optical atomic transitions from high ionization potential (IP$geq$54.8,eV) ions, such as Ca$^{mathrm{4+}}$, Ne$^{mathrm{4+}}$, Fe$^{mathrm{6+}}$, Fe$^{mathrm{10+}}$, Fe$^{mathrm{13+}}$, Ar$^{mathrm{9+}}$, and S$^{mathrm{11+}}$, are known as optical coronal lines (CLs). The spectral energy […]
Continue.. Why are optical coronal lines faint in active galactic nuclei?