Search Publications
Calibration of HST narrow band filters using the Orion Nebula.
Hu, Xihai
HST images in three emission line filters: Hα, [O III] and [N II] have been calibrated. The CCD sensitivity was determined by comparing regions within HST frames with the corresponding surface brightness determined from ground based Orion Nebula observations. Corrections for continuum within each filter were made. It was necessary to correct the […
HST imaging of the wind-blown lobe NGC 6165.
Hester, J.; Scowen, P.; Code, A. +1 more
WFC observations of the lobe NGC 6165 have resolved clumps that are being photoevaporated by the intense UV radiation from HD 148937, in addition to the erosive effects of the strong stellar wind. The central object is a massive superluminous young star that is thought to be undergoing mass loss as it descends onto the main sequence. Analysis of s…
The IUE spectrum of the Wolf-Rayet system HD 193077.
Koenigsberger, G.
The results of a detailed line-identification study of the IUE(1100-1900 A) spectrum of the Wolf-Rayet star HD 193077 (WR 138) is presented. The emission line spectrum is shown to be dominated by Fe V+Fe VI lines below 1500 A. The interstellar-line spectrum contains a large variety of atomic and ionic species, ranging from C I to Si IV and C IV, a…
A spectrophotometric study of the planetary nebula N66 in the Large Magellanic Cloud.
Ruiz, M. T.; Peña, M.
The authors present spectrophotometric data of the LMC planetary nebula N66. Combining these observations with IUE data and ionization structure models, they derive the chemical composition of the nebula and parameters of the central star.
Multiwavelength observations of the AM Herculis type system: MR Serpentis.
Schwarzenberg-Czerny, A.; Ward, M.; Jones, D. H. P. +4 more
The authors describe simultaneous ultaviolet and optical, as well as other observations of MR Ser during a high state. No substantial linear polarization was observed during an orbital cycle, but the circular polarization was high. The ultraviolet spectrum presents strong lines in emission of N V λ1240, Si IV λ1400, C IV λ1550 and He II λ1640, typ…
On the planetary nebula NGC 3918.
Pena, M.; Torres-Peimbert, S.
We have obtained for this nebula high dispersion lUE spectra in the short and long wavelength ranges and with different exposure times. We have measured the emission line intensities and analyzed them. The density derived fiom different ions confirm that the nebula has no systematic density variations. The collisionally excited lines of [Mg V] 278…
New observations of the CIV and N V resonance doublets in the planetary nebula NGC 3918.
Pena, M.; Torres-Peimbert, S.
We present new short wavelength high dispersion lUE measurements of the resonance doublets 1238/1243 of N V and 1548/1551 of C IV. The observed intensity ratios are of 1.87±0.15 for N V and 1.83±0.11 for C IV; compatible, within the observational uncertainties with the expected ratio of 2.
Spectral evolution of galaxies. II. an atlas of IUE spectra of late type stars and nearby early type stellar systems.
Bruzual, G. A.
Low dispersion lUE spectra are presented in both pictorial and tabular form for late type stars, globular clusters, and elliptical galaxies. Average spectra are computed for types of objects with more than one observed spectrum.
High dispersion IUE observations of the planetary nebula NGC 3918.
Torres-Peimbert, S.; Peña, M.
The authors have measured absolute fluxes of the lines present in a IUE high dispersion short wavelength exposure of NGC 3918. The mean electron density derived is 5×103 cm-3, in agreement with previous determinations. An anomalous value of 1.2 ± 0.1 for the ratio λλ1239/1243 of N V is found. Its implications are discussed.