Search Publications
The CIV resonance lines in B and early A supergiants.
Underhill, A. B.
A rapidly moving hot wind, with Vinfinity near 620 km/s, is seen by means of C IV resonance lines at types B2 Ia and B3 Ia. The C IV lines are not obvious in the winds from supergiants of types B5 Ia to A2 Ia. In the A0 Ia star HD 21389 the C IV lines appear sporadically as sharp, undisplaced emission lines, suggesting the sporadic pres…
Far-ultraviolet observations of Cygnus X-2.
Maraschi, L.; Tanzi, E. G.; Treves, A.
Two far-ultraviolet (1150-1950 A) spectra of V 1341 Cyg identical with Cyg X-2, taken with the International Ultraviolet Explorer, at orbital phase 0.3 and 0.6 show an intensity variation of a factor of 2. Strong emission lines (N V, Si IV, and He II) are apparent on a poorly defined continuum. The observations can be interpreted in terms of UV em…
Ultraviolet spectroscopy of F and G supergiants with the IUE. I. First results on Cepheid variables.
Parsons, S. B.
The analysis deals with the bright Cepheids observed from the IUE satellite, over several days, at a speed and spectral resolution suitable to study both the cores of Mg II at 2796 and 2803 A and the presence and strength of the more prominent emission lines in the far ultraviolet. The observations are discussed in some detail. Some qualitative re…
QSO evolution and the intergalactic medium.
Sherman, R. D.
A model is developed of a cold, photoionized intergalactic medium in which only discrete, evolving sources (quasars) produce the observed extragalactic hard X-ray background. Constraints on the model are imposed by observed optical depth limits to various redshifts, far UV and visible flux measurements, X-ray background and source counts in the re…
The log N-log S graph for the COS-B galactic-ray sources.
Caraveo, P. A.; Bignami, G. F.
As a tool to the study of the collective properties of the 26 low-galactic-latitude γ-ray sources in the second CO S-B catalog their integral number-intensity relation, log N( > S, is investigated. The difficulty of accounting for the large flux errors is overcome by a simple Monte Carlo method. Especially when experimental selection effects ar…
The ultraviolet spectrum and flux of HD 152667 (=X-ray source 1653-40?)
Dupree, A. K.; Hutchings, J. B.
IUE data are presented on the massive binary system HD 152667 (spectral type BO I), covering many phases of the 8 day orbit. Low-dispersion data are used to drive T(eff), E(B-V), and the UV light curve. The secondary object is much fainter than the primary at all wavelengths. The stellar wind shows complex multiple components and appears to be uni…
IUE observations of a luminous M supergiant that exhibits emission continuum in the far ultraviolet.
Kafatos, M.; Michalitsianos, A. G.; Hobbs, R. W.
IUE observations of the late-type M supergiant star TV Gem which reveal an intense continuum in the far ultraviolet are discussed. TV Gem was observed in low dispersion in November 1979 and in high and low dispersion in January 1980 by the short and long wavelength cameras of the IUE spectrometer. An essentially featureless UV continuum was obtain…
Erratum - IUE Low-Dispersion Spectra of Four Luminous Stars in Symmetric Nebulae
Johnson, H. M.
Outer atmospheres of cool stars. I. The sharp division into solar-type and non-solar-type stars.
Linsky, J. L.; Haisch, B. M.
On gamma-ray sources, supernova remnants, OB associations, and the origin of cosmic rays.
Montmerle, T.
Spatial coincidences between supernova remnants and OB associations or H II regions are sought, and a list of about 30 objects (referred to as 'SNOBs') is obtained. On the basis of COS B data it is found that five, or perhaps six, of 11 as-yet unidentified gamma-ray sources are associated with SNOBs and that as many as three-fourths of the best-id…