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Background and Scattered Light Subtraction in the High-Resolution Echelle Modes of the Space Telescope Imaging Spectrograph
J. Christopher Howk, Kenneth R. Sembach
We present a simple, effective approach for estimating the on-order backgrounds of spectra taken with the highest-resolution modes of the Space Telescope Imaging Spectrograph (STIS…
Stagnation and Infall of Dense Clumps in the Stellar Wind of tau Scorpii
J. Christopher Howk, Joseph Cassinelli, Jon Bjorkman +1
Observations of the B0.2V star tau Scorpii have revealed unusual stellar wind characteristics: red-shifted absorption in the far-ultraviolet O VI resonance doublet up to +250 km/s,…
Modeling the Warm Ionized Interstellar Medium and Its Impact on Elemental Abundance Studies
Kenneth R. Sembach, J. Christopher Howk, Robert S. I. Ryans +1
We present model calculations of ionization fractions for elements in the warm (log T = 4), low-density photoionized interstellar medium (WIM) of the Milky Way. We model the WIM as…
Ionized Gas in Damped Lyman-alpha Systems and Its Effects on Elemental Abundance Studies
J. Christopher Howk, Kenneth R. Sembach
Recent high-resolution observations of metal absorption lines in high-redshift damped Ly-alpha systems have shown that Al III, a tracer of moderately-ionized gas, very often has a…