87 citations · 349 across the 14 of their papers we have counts for
9 papers · 1 filter
On the Importance of the Interclump Medium for Superionization: O VI Formation in the Wind of Zeta Pup
J. Zsargo, D. J. Hillier, J. -C. Bouret +3
We have studied superionization and X-ray line formation in the spectra of Zeta Pup using our new stellar atmosphere code (XCMFGEN) that can be used to simultaneously analyze optic…
Axi-symmetric Models of B[e] Supergiants: I. The Effective Temperature and Mass-loss Dependence of the Hydrogen and Helium Ionization Structure
J. Zsargo, D. J. Hillier, L. N. Georgiev
We calculate the hydrogen and helium ionization in B[e] envelopes and explore their dependence on mass-loss and effective temperature. We also present simulated observations of the…
2D non-LTE Modeling for Axi-symmetric Winds. II. A Short Characteristic Solution for Radiative Transfer in Rotating Winds
J. Zsargo, D. J. Hillier, L. N. Georgiev
We present a new radiative transfer code for axi-symmetric stellar atmospheres and compare test results against 1D and 2D models with and without velocity fields. The code uses the…
A Short Characteristic Solution for the 2.5D Transfer Equation in the Envelopes of O and B Stars
J. Zsargo, D. J. Hillier, L. N. Georgiev
We discuss work toward developing a 2.5D non-LTE radiative transfer code. Our code uses the short characteristic method with modifications to handle realistic 3D wind velocities. W…
A Search for O VI in the Winds of B-Type Stars
J. Zsargo, A. W. Fullerton, N. Lehner +1
We have conducted a survey of FUSE spectra of 235 Galactic B-type stars in order to determine the boundaries in the H-R diagram for the production of the superion O VI in their win…
Further Evidence for Chemical Fractionation from Ultraviolet Observations of Carbon Monoxide
S. R. Federman, David L. Lambert, Yaron Sheffer +4
Ultraviolet absorption from interstellar 12CO and 13CO was detected toward rho Oph A and chi Oph. The measurements were obtained at medium resolution with the Goddard High Resoluti…
Non-Thermal Chemistry in Diffuse Clouds with Low Molecular Abundances
J. Zsargo, S. R. Federman
High quality archival spectra of interstellar absorption from C I toward 9 stars, taken with the Goddard High Resolution Spectrograph on the Hubble Space Telescope, were analyzed.…
FUSE Snap-Shot Survey of O VI Variability in the Winds of 66 OB-Type Stars
N. Lehner, A. W. Fullerton, D. Massa +2
We have used the Far Ultraviolet Spectroscopic Explorer (FUSE) to conduct a snap-shot survey of O VI variability in the winds of 66 OB-type stars in the Galaxy and the Magellanic C…
Highly-Ionized Gas in the Galactic Halo: A FUSE Survey of O VI Absorption toward 22 Halo Stars
J. Zsargo, K. R. Sembach, J. C. Howk +1
Far Ultraviolet Spectroscopic Explorer spectra of 22 Galactic halo stars are studied to determine the amount of O VI in the Galactic halo between ~0.3 and \~10 kpc from the Galacti…