124 citations · 355 across the 11 of their papers we have counts for
11 papers
The physical properties of T Pyx as measured by MUSE I. The geometrical distribution of the ejecta and the distance to the remnant
L. Izzo, L. Pasquini, E. Aydi +8
T Pyx is one of the most enigmatic recurrent novae, and it has been proposed as a potential Galactic type-Ia supernova progenitor. Using spatially-resolved data obtained with MUSE,…
Thermodynamically-consistent semi-classical -changing rates
R. J. R. Williams, F. Guzmán, N. R. Badnell +3
We compare the results of the semi-classical (SC) and quantum-mechanical (QM) formalisms for angular-momentum changing transitions in Rydberg atom collisions given by Vrinceanu & F…
H, He-like recombination spectra I: -changing collisions for hydrogen
F. Guzmán, N. R. Badnell, R. J. R. Williams +3
Hydrogen and helium emission lines in nebulae form by radiative recombination. This is a simple process which, in principle, can be described to very high precision. Ratios of He I…
Implications of Coronal Line Emission in NGC 4696
M. Chatzikos, R. J. R. Williams, G. J. Ferland +7
We announce a new facility in the spectral code CLOUDY that enables tracking the evolution of a cooling parcel of gas with time. For gas cooling from temperatures relevant to galax…
On the Observability of Optically Thin Coronal Hyperfine Structure Lines
Marios Chatzikos, Gary Ferland, Robin Williams +1
We present Cloudy calculations for the intensity of coronal hyperfine lines in various environments. We model indirect collisional and radiative transitions, and quantify the colli…
Pumping up the [N I] nebular lines
G. J. Ferland, W. J. Henney, C. R. O'Dell +3
The optical [N I] doublet near 5200 Å is anomalously strong in a variety of emission-line objects. We compute a detailed photoionization model and use it to show that pumping by fa…
Hydrogen Two-Photon Continuum Emission from the Horseshoe Filament in NGC 1275
R. M. Johnstone, R. E. A. Canning, A. C. Fabian +5
Far ultraviolet emission has been detected from a knot of Halpha emission in the Horseshoe filament, far out in the NGC 1275 nebula. The flux detected relative to the brightness of…
The energy source of the filaments around the giant galaxy NGC1275
A. C. Fabian, J. S. Sanders, R. J. R. Williams +3
The brightest galaxy in the nearby Perseus cluster, NGC1275, is surrounded by a network of filaments. These were first observed through their Halpha emission but are now known to h…
Implications of infalling Fe II - emitting clouds in active galactic nuclei: anisotropic properties
Gary J. Ferland, Chen Hu, Jian-Min Wang +4
We investigate consequences of the discovery that Fe II emission in quasars, one of the spectroscopic signatures of "Eigenvector 1", may originate in infalling clouds. Eigenvector…
Jet cocoons and the formation of Narrow Line Clouds in Seyfert galaxies
W. Steffen, J. L. Gomez, R. J. R. Williams +2
We present non-adiabatic hydrodynamic simulations of a supersonic light jet propagating into a fully ionized medium of uniform density on a scale representative of the narrow line…
Highly supersonic motions within the outer features of the Eta Carinae nebulosity
J. Meaburn, P. Boumis, J. R. Walsh +4
Spatially resolved H and [N{\sc ii}] line profiles have been obtained over striking features in the outer regions of the Eta Carinae nebula. The highly irregular outer `shell' o…