Coronal loops, seen in solar coronal images, are believed to represent emission from magnetic flux tubes with compact cross-sections. We examine the 3D structure of plasma above an active region a radiative magnetohydrodynamic simulation locate volume counterparts for loops. In many cases, loop cannot be linked individual thin strand volume. While loops present synthetic bright structures fewer...

We present photoionization models of the optical and IR coronal line spectrum in NGC 1068 and the Circinus galaxy. The line fluxes have been calculated using (a) a nonthermal (nuclear) continuum source and (b) the non-thermal continuum plus a UV bump due to a stellar cluster. We take into account the effect of attenuation of these continua by gas with column density 1022 cm−2 located between th...