Search Publications
The ultraviolet excess of luminous quasars. II. Evidence for massive accretion disks.
Malkan, M. A.
This paper presents new infrared, optical, and ultraviolet spectra of three high-redshift quasars. They are analyzed along with three published quasar spectra. After accounting for other sources of radiation, the continua are fitted with spectra predicted for optically thick steady-state accretion disks which include the effects of general relativ…
Peculiar ultraviolet interstellar extinction.
Savage, B. D.; Fitzpatrick, E. L.; Massa, D.
In connection with investigations of the physical characteristics of interstellar dust, a study of objects with peculiar extinction might provide new insights about the composition, size distribution, formation, and destruction of the particulate matter. Meyer and Savage (1981) have found that the dust toward many stars exhibits peculiar UV extinc…
Herbig-haro objects.
Schwartz, R. D.
Progress in the understanding of Herbig-Haro (HH) objects is reviewed. The results of optical studies of the proper motions and alignments, variability, and polarization of HH objects and the results of spectroscopic studies are discussed. Ground-based infrared studies and far-infrared observations are reviewed. Findings on the properties of molec…
Prominent ultraviolet emission lines from type 1 Seyfert galaxies.
Gull, T. R.; Boggess, A.; Wu, C. -C.
IUE Explorer data with a 6-A resolution are reported for Ly-alpha, C IV 1550 A, C III semiforbidden line 1909 A, and Mg II 2800 A, as well as the continuum at 1450 A, for 20 Seyfert galaxies and one quasar. Good correlation is found between the continuum and the line fluxes, indicating that photoionization is the dominant heating mechanism for the…
IUE and other new observations of the slow nova RR Tel.
Penston, M. V.; Jordan, C.; Macchetto, F. +8 more
IUE satellite UV spectra of RR Tel covering 1150-3200 A at high and low dispersion through both large and small apertures are reported, and a list of 431 lines is presented which gives measured wavelength, intensity, and full width at half maximum. Over three-quarters of the lines are identified, and a correlation is noted between line width and i…
R 127 : an S DOR type variable intermediate between Of and WN.
Stahl, O.; Wolf, B.; Cassatella, A. +4 more
The results of extensive photometric and high resolution spectroscopic observations of the S Dor variable R 127 are presented and discussed. These observations show the star to be hotter than any of its type previously discovered. Its bolometric magnitude is 10.6, its effective temperature is 16,000 K, and its radius is 150 solar radii. The stella…
Coordinated Einstein and IUE observations of a disparitions brusques type flare event and quiescent emission from Proxima Centauri.
Golub, L.; Stencel, R. E.; Linsky, J. L. +4 more
The Einstein Imaging Particle Counter observed a major X-ray flare in its entirety during a 5-hr period of simultaneous observations, with the IUE, of the dM5e flare star Proxima Centauri in August, 1980. The detailed X-ray light curve, temperature determinations during various intervals, and UV line fluxes obtained before, during, and after the f…
A far Ultraviolet extinction law : what does it mean ?
Greenberg, J. M.; Chlewicki, G.
The dust grains in the diffuse cloud medium are characterized by a far-ultraviolet (FUV) extinction "law" so that all curves have the same functional form for inverse wavelengths λ-1 ⪆ 6 µm-1. A direct theoretical consequence of this fact is that there is very little scattering by either the particles responsible for th…
The discovery of S2 in comet IRAS-Araki-Alcock 1983d
Feldman, P. D.; A'Hearn, M. F.; Schleicher, D. G.
Ultraviolet spectra of comet IRAS-Araki-Alcock 1983d, obtained with the International Ultraviolet Explorer spacecraft when the comet was only 0.032 AU from earth, show strong emission bands due to S2, the first detection of this species in an astronomical object. The spatial profiles imply that the S2 is released directly from the nucleus and has …
First observations of stellar coronal structure : the coronae of AR Lacertae.
Basri, G. S.; Walter, F. M.; Gibson, D. M.
In connection with the present investigation, X-ray, radio, and ultraviolet observations of AR Lacertae over one orbital cycle have been obtained. The X-ray light curve shows a deep primary minimum and a broad, shallow secondary minimum. The quiescent corona of the G2 IV component is small and asymmetric. This corona extends some 0.02 stellar radi…