Highly Ionised Gas as a Diagnostic of the Inner NLR

The spectra of AGN from the ultraviolet to the near infrared, exhibit emission lines covering a wide range of ionisation states, from neutral species such as [O I] 6300A, up to [Fe XIV] 5303A. Here we report on some recent studies of the properties of highly ionised lines (HILs), plus two case studies of individual objects. Future IFU observations at high spatial and good spectral resolution, will probe the excitation and kinematics of the gas in the zone between the extended NLR and unresolved BLR. Multi-component SED fitting can be used to link the source of photoionisation with the strengths and ratios of the HILs.Comment: Proceedings of the IAU Symposium: Co-evolution of Central Black Holes and Galaxie

Application of edge-based finite elements and vector ABCs in 3D scattering

A finite element absorbing boundary condition (FE-ABC) solution of the scattering by arbitrary 3-D structures is considered. The computational domain is discretized using edge-based tetrahedral elements. In contrast to the node-based elements, edge elements can treat geometries with sharp edges, are divergence-less, and easily satisfy the field continuity condition across dielectric interfaces. They do, however, lead to a higher unknown count but this is balanced by the greater sparsity of the resulting finite element matrix. Thus, the computation time required to solve such a system iteratively with a given degree of accuracy is less than the traditional node-based approach. The purpose is to examine the derivation and performance of the ABC's when applied to 2-D and 3-D problems and to discuss the specifics of our FE-ABC implementation

A scheme to alter the resonant frequency of the microstrip patch antenna

Simple schemes are presented for altering the resonant frequency of a rectangular patch antenna without the need to change its size. In particular, by placing a perturbance below the patch it is shown that as much as 20 percent increase and 30 percent decrease from the resonant frequency of the unperturbed patch can be achieved. The specific configurations considered in this letter include a cavity-backed, aperture-backed, and protrusion-backed patch, and for each case design curves are presented

Lamellar phase separation and dynamic competition in La0.23Ca0.77MnO3

We report the coexistence of lamellar charge-ordered (CO) and charge-disordered (CD) domains, and their dynamical behavior, in La0.23Ca0.77MnO3. Using high resolution transmission electron microscopy (TEM), we show that below Tcd~170K a CD-monoclinic phase forms within the established CO-orthorhombic matrix. The CD phase has a sheet-like morphology, perpendicular to the q vector of the CO superlattice (a axis of the Pnma structure). For temperatures between 64K and 130K, both the TEM and resistivity experiments show a dynamic competition between the two phases: at constant T, the CD phase slowly advances over the CO one. This slow dynamics appears to be linked to the magnetic transitions occurring in this compound, suggesting important magnetoelastic effects.Comment: 4 pages, 4 figure