Search Publications
Spatially Resolved Ultraviolet Spectroscopy of the Liner Galaxy NGC 3998
Filippenko, A. V.; Branduardi-Raymont, G.; Reichert, G. A. +3 more
We report results of recent IUE observations of the low-ionization nuclear emission-line region (LINER) galaxy NGC 3998. Spatial structure in the long-wavelength emission is apparent; the spatial profiles in the LWP images show a two-component structure, with an unresolved central component superposed on extended underlying emission. We have used …
Carbon and Nitrogen Abundances Determined from Transition Layer Lines
Mena-Werth, Jose; Boehm-Vitense, Erika
The possibility of determining relative carbon, nitrogen, and silicon abundances from the emission-line fluxes in the lower transition layers between stellar chromospheres and coronae is explored. Observations for main-sequence and luminosity class IV stars with presumably solar element abundances show that for the lower transition layers Em = BT<…
The Structure of the Inner Arcsecond of R Aquarii Observed with the Hubble Space Telescope
Burgarella, Denis; Paresce, Francesco
The inner arcsec of R Aquarii has been observed with the Faint Object Camera on the Hubble Space Telescope. A simple and reliable linear deconvolution method is used to resolve the two features, designated C1 and C2 from radio observations, into several condensations. C1 is composed of four objects, designated C1a, C1b located at 0.099 arcsec from…
A VLA 3.6 Centimeter Survey of N-Type Carbon Stars
Brown, Alexander; Luttermoser, Donald G.
The results are presented of a VLA-continuum survey of 7 N-type carbon stars at 3.6 cm. Evidence exists for hot plasma around such stars; the IUE satellite detected emission lines of singly ionized metals in the optically brightest carbon stars, which in solar-type stars indicate the existence of a chromosphere. In the past, these emission lines w…
Possible First Detection of Ultraviolet Pulses from an Intermediate Polar: V603 Aquila
Udalski, A.; Schwarzenberg-Czerny, A.; Monier, R.
We report possible independent detection of a pulsation in the UV continuum radiation of the intermediate polar star, V603 Aql, at 2.2 sigma level. Since the period of the pulsation of 62.9 minutes is very close to the period of X-ray and optical modulations discovered earlier, its detection combined with previous data confirms reality of UV, X-ra…
The Origin of the Far-Ultraviolet Continuum in Solar and Stellar Flares
Bromage, G. E.; Doyle, J. G.; Phillips, K. J. H.
A continuum in the far-ultraviolet region observed in IUE spectra of dMe stars in a flaring state is discussed and compared with that observed in solar flares. Similar continuous emission observed in solar flare far-ultraviolet spectra has been identified with neutral silicon recombination radiation excited by intense lines. This also appears to b…
The Sun as a Star: High Spectral Resolution Solar Data Degraded to Low-Dispersion IUE Resolution
Doyle, J. G.; Cook, J. W.
High spectral resolution (about 0.06 A) solar data for an active region and a large two-ribbon flare degraded to the typical resolution of low-dispersion (about 5 A) spectra of the IUE satellite are presented. This clearly shows the amount of detail yet to be acquired in stellar spectra and indicates the main spectral regions where line blending i…
Faint Object Spectrograph Observations of the Large-Redshift Gravitational Lens Candidate 1208+1011
Maoz, Dan; Schneider, Donald P.; Jannuzi, Buell T. +2 more
We report HST spectroscopic observations of the z = 3.8 gravitational lens candidate 1208+1011. Low-dispersion (R = 200) Faint Object Spectrograph data, covering the wavelength range 3700-7800 A, were obtained for each of the two components (V ~18.3 and 19.8 mag) and for a comparison (blank) field; the fainter component and the blank field are bot…
X-Ray Observations of Planetary Nebulae with Binary Nuclei
Nousek, J. A.; Apparao, K. M. V.; Berthiaume, G. D.
Einstein and EXOSAT satellite observations of X-ray emission from the planetary nebulae A63 and LoTr 5 are reviewed. Both of these systems contain binary central stars. No flux was detected from A63 (central star UU Sge). LoTr 5 (central star IN Com) is a previously unreported X-ray emitter; it showed no statistically significant X-ray variability…
Highly Ionized Gas in the GUM Nebula and Elsewhere: A Comparison of IUE and Copernicus Satellite Results
Savage, Blair D.; Edgar, Richard J.
The data from six high-dispersion IUE echelle spectra are averaged in order to obtain an interstellar absorption line spectrum with an S/N of about 30 and a resolution of about 25 km/s. The interstellar lines of C IV and Si IV are very strong and broad and N V is detected. The profiles for these species and Al III are compared to the Copernicus sa…