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Revised chemical models of ζ Oph based on HST data

Williams, D. A.; Wagenblast, R.

Hubble Space Telescope observations by Savage, Cardelli and Sofia (1992) and Cardelliet al. (1993) have led to improved gas phase abundances for many elements in the diffuse cloud towards the star ζ Oph. Most remarkably, it was found that oxygen is much more strongly depleted than previousCopernicus observations indicated. As a consequence, chemic…

Hubble Space Telescope observations of Magellanic cloud planetary nebulae: Stellar winds

Vassiliadis, Emanuel

Narrow-band [OIII] 500.7 nm images and ultraviolet spectrophotometry are obtained for ≈20 planetary nebulae (PNe) in the Magellanic Clouds using the Hubble Space Telescope (HST). Four objects show P Cygni-like features in the ultraviolet HST data, and/or broad emission complexes near the HeII 468.6 nm and CIV 580.6 nm lines in ground-based spectra…

Hubble space telescope observations of AGN`s in the ultraviolet: BL LAC and Q2345+007

Boyd, Patricia T.; Nelson, M. J.; Percival, J. W. +3 more

We report the first polarimetric observations in the ultraviolet of two AGN's, the blazar BL Lac and the gravitational lens candidate Q2345+007. We find strong (p>3%) and variable UV polarization in BL Lac, two of the characteristics exhibited by blazars in the visible. The polarization of BL Lac in the UV decreased significantly (from 18% to &…