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Terminal Velocities of Wolf-Rayet Star Winds from Low Resolution IUE Spectra

Niedzielski, A.; Rochowicz, K.

Attracted by the simplicity of the recently published by Prinja (1994) method of determination of terminal wind velocities in hot stars from low resolution IUE spectra we investigate its application to WR stars. With a large sample of low resolution IUE spectra of WR stars we found even simpler, that is linear instead of square, empirical relation…

Non-standard Extinction by Circumnuclear Dust in Active Galactic Nuclei

Szczerba, R.; Madejski, G.; Czerny, B. +2 more

Observational data imply that Active Galactic Nuclei are likely to have a substantial amount of dust within some 0.1-100pc. This dust modifies the observed spectrum of the nucleus by reprocessing a significant fraction of its intrinsic bolometric luminosity. The details of the emerging spectrum in the infrared and in the ultraviolet are dependent …

Interstellar Ultraviolet Extinction Towards the Nitrogen Sequence Wolf-Rayet Stars

Niedzielski, Andrzej

With the archive IUE spectra of WR stars collected by Niedzielski and Rochowicz (1994) we obtain the UV extinction curve for WN stars. Using the two-color diagram method we can reach the goal almost independently, assuming only similar (b-v)_0 for all single galactic WN stars, what is discussed on the basis of latest results. The resulting extinct…

Local Interstellar Medium Toward beta GEM and sigma GEM

Glebocki, R.; Gnacinski, P.; Sikorski, J.

We present and analyze high-dispersion IUE observations of the interstellar magnesium, deuterium and hydrogen absorption profiles toward two late-type stars beta Gem (10.8 pc) and sigma Gem (59 pc) separated by 0.5 arcdeg on the sky. We confirm the velocity shift of the local interstellar cloud obtained for a bulk flow by Crutcher (1982). From the…