Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
The Ionization Balance Of A Non-Equilibrium Plasma, Gary J. Ferland
The Ionization Balance Of A Non-Equilibrium Plasma, Gary J. Ferland
Physics and Astronomy Faculty Publications
Commentary on: Arnaud M. and Rothenflug R., 1985, A&AS, 60, 425.
Grains In Ionized Nebulae: Spectral Line Diagnostics, J. B. Kingdon, Gary J. Ferland, W. A. Feibelman
Grains In Ionized Nebulae: Spectral Line Diagnostics, J. B. Kingdon, Gary J. Ferland, W. A. Feibelman
Physics and Astronomy Faculty Publications
The depletion of condensable elements onto grains in gaseous nebulae can provide evidence that dust is well mixed with the ionized gas. Al and CA are two of the most depleted elements in the general interstellar medium, and it is therefore important to measure their abundances within the ionized region of nebulae. We compute a large grid of photoionization models and identify sets of line ratios which are relatively insensitive to stellar and nebular parameters, and are thus excellent diagnostics for determining relative abundances. Based on the absence of the [Ca II] λλ7291, 7324 doublet and the detection of …
Nebular Properties And The Ionizing Radiation Field In The Galactic Center, Joseph C. Shields, Gary J. Ferland
Nebular Properties And The Ionizing Radiation Field In The Galactic Center, Joseph C. Shields, Gary J. Ferland
Physics and Astronomy Faculty Publications
Nebulosity in the central parsec of the Milky Way exhibits a low-ionization spectrum that has led previous analyses of this region to conclude that this material is photoionized by a relatively soft continuum. We have reanalyzed the infrared emission-line spectrum of te Galactic center in order to consider whether the data could actually be explained with photoionization by a relatively hard, yet dilute continuum, and additionally to constrain the properties of the reaiating plasma. We conclude that the composite infrared spectrum does not place strong restrictions on the nature of the ionizing continuum and that much of the ionized gas …