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Full-Text Articles in Physics
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 …
The Hydrogen Line Spectra Of Narrow-Line Radio Galaxies, Gary J. Ferland, Donald E. Osterbrock
The Hydrogen Line Spectra Of Narrow-Line Radio Galaxies, Gary J. Ferland, Donald E. Osterbrock
Physics and Astronomy Faculty Publications
We report the results of the first detection of Lyα in a narrow-line radio galaxy. Nearly simultaneous optical and UV observations of 3C 192 and 3C 223 allow the measurement of both Balmer and Lyman decrements. These line ratios are approximate functions of the interstellar reddening and of a parameter which is proportional to the amount of H I collisional excitation present. The reddening of 3C 192 is slightly larger than that due to our Galaxy, although 3C 223 may have a larger value. Both galaxies have intrinsic Balmer and Lyman decrements which are significantly steeper than case B, …