124 citations · 355 across the 11 of their papers we have counts for
5 papers · 1 filter
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…
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…