Search Publications
Kinematical Structure of Wolf-Rayet Winds. II. Internal Velocity Scatter in WN Stars
Niedzielski, A.; Nugis, T.; Skorzynski, W.
The shortward edge of the absorption core velocities - v_black as determined from low resolution archived IUE spectra from the INES database are presented for three P Cyg profiles of NV 1240, HeII 1640 and NIV 1720 for 51 Galactic and 64 LMC Wolf-Rayet stars of the WN subtype. These data, together with v_black of CIV 1550 line presented in Niedzie…
Interstellar Silicon Abundance
Gnacinski, P.
We present 34 measurements of silicon gas phase column densities in the interstellar medium. We have used spectra containing the SiII 1808 Ang line which were obtained with the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST). Extinction curve parameters are determined for analyzed lines of sight and relation bet…
Kinematical Structure of Wolf-Rayet Winds. I.Terminal Wind Velocity
Niedzielski, A.; Skorzynski, W.
New terminal wind velocities for 164 Wolf-Rayet stars (from the Galaxy and LMC) based on PCyg profiles of lambda1550 CIV resonance line were derived from the archive high and low resolution IUE spectra available form the INES database. The high resolution data on 59 WR stars (39 from the Galaxy and 20 from LMC) were used to calibrate the empirical…
Interstellar Carbon Abundance
Gnacinski, Piotr
We present 10 new measurements of carbon gas phase column density in the interstellar medium. We have used spectra made with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope containing the CII 1334.5 Ang and CII* 1335.7 Ang lines. The continuum reconstruction method has been used to obtain the carbon column density from t…
Spectral Components in the Optical Emission of the Seyfert Galaxy NGC 5548 and the Comparison of Intrinsic Nuclear Spectra with Accreting Corona Model
Czerny, B.; Kuraszkiewicz, J.; Loska, Z.
We study the extensively monitored Seyfert galaxy NGC 5548 and compare its nuclear emission with models of accretion disk with accreting corona. To obtain the intrinsic nuclear spectra from the observed spectra we had to estimate and subtract the contribution from circumnuclear components such as stars, the Balmer continuum and blended FeII lines,…
Ultraviolet DIB at 1369 A Arising in Molecular Clouds
Gnacinski, P.; Sikorski, J.; Kaczmarczyk, G.
Hubble Space Telescope (HST) and IUE observations of the weak unidentified interstellar line 1369 A in nine early type stars are discussed. This absorption feature might be a diffuse interstellar band (DIB). We have found good correlation between the equivalent widths of the 1369 A line and the interstellar CO A1Pi-X1Sigma (6…
Ultraviolet Ionization Stratification in Wolf-Rayet Winds
Rochowicz, Krzysztof
Ionization stratification can be used to study the structure of WR winds. In an accelerated outflow the stratification is observable through the Doppler effect as an inverse correlation of ionization potential (IP) with line width (FWHM). However, not only the average line widths of different ions, but also the line widths of one series of HeII sh…
Starspot and Chromospheric Activity of lambda And in 1978--1995
Glebocki, R.; Sikorski, J.
UBV photometry and UV spectra from the IUE satellite are analyzed for search of relation between photospheric and chromospheric activity in lambda And. We find no correlation between intensity variations of chromospheric and TR emissions and visibility of spots. Intensities of TR lines are proportional to the MgII emissions. UV continuum follows f…
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 …