Search Publications
The Moderately Interacting Algol Binary RS Cephei
Plavec, Mirek J.; Dobias, Jan J.
In agreement with previous observers, it is found that the eclipsing binary RS Cep is an Algol-type semidetached system. From IUE spectra and Lick Observatory optical scans, the spectral types of the components are determined as B9.7e V + G8 III-IV. The effective temperature of the primary star is found to be 9670 K (with an uncertainty of about 1…
Reexamination of evidence for a radiatively decaying neutrino
Murthy, J.; Henry, R. C.
Nonstandard electroweak models permitting relatively rapid neutrino decay, with emission of ultraviolet photons, stimulate new interest in astronomical methods of detection of the emitted photons. We do not support the detection of a step in the cosmic background spectrum that has been reported recently. New and more sensitive measurements are urg…
Flux distribution in the Algol binary system RW Persei.
Plavec, Mirek J.; Dobias, Jan J.
The authors have obtained IUE low-dispersion spectra and optical ITS scans of the semidetached Algol-type binary system RW Per. They have determined the spectral type of the primary component to be B9.6e, with good accuracy. The spectral type of the cooler component has been determined with less accuracy as K2 III - IV. The system is heavily redde…
Combined satellite and ground-based observations of the quiescent, high latitude symbiotic variable AG Draconis=BD+67°922
Lambert, D. L.; Cassinelli, J. P.; Anderson, C. M. +1 more
Satellite observations, fromEinstein,IUE, andIRAS, have been combined with ground-based observations to derive the quiescent energy distribution of the symbiotic star AG Draconis. A detailed comparison is made between the combined observations and various steady-state composite models, including blackbody accretion disks.
Synchrotron X-ray haloes around gamma ray sources
Warwick, R. S.; Wolfendale, A. W.; Norton, A. J. +3 more
High energy γ-ray sources, epitomized by Cygnus X-3, may well be releasing significant fluxes of 1014eV electrons into their environment and these electrons can give synchrotron X-rays when deflected in the general interstellar magnetic field. A greatly simplified model for this mechanism is described in terms of electron diffusion para…
The ultraviolet variability X-ray pulsars : observations of VELA X-1,A 0535+26 and 4U 1145-619.
Coe, M. J.; Payne, B. J.
The IUE satellite has been used in a special trailed mode to search for modulation in the ultraviolet flux from the binary X-ray pulsars Vela X-1, A 0535+26 and 4U 1145-619. The trailing technique allows the UV spectrum from these sources to be sampled during the X-ray pulse cycle, with a resolution ≡1/10th of the pulse period. Modulations of 15 -…
Far-UV variability of theta CrB in 1985-86 : a progression toward higher velocities.
Doazan, V.; Thomas, R. N.; Rusconi, L. +1 more
New far UV observations of θ CrB obtained with the IUE in 1985 - 1986 are presented. They show that the far UV spectrum of that star has usually continued to exhibit the apparently low excitation state observed from mid-84 to mid-85. However, the C IV resonance lines are occasionally conspicuous and exhibit an even higher outflow velocity than dur…
The ultraviolet gallium stars.
Jaschek, M.; Jaschek, C.
On the basis of IUE low dispersion spectra, the authors define a group of UV peculiar stars in the range of middle and late B-type stars, characterized by strong Ga II λ1414 line. This group has no counterpart in the optical λλ3600 - 4800 range.
X-Ray Observations of Cataclysmic Variables
Osborne, J. P.
The X-ray observatory EXOSAT spent over 1000 hours observing cataclysmic variables. Some of the major results reviewed here are: soft X-ray light curve changes in AM Her objects, orbital effects in the X-ray light curves of intermediate polars and U Gem, regular behaviour in the inter-outburst X-ray flux of VW Hyi, and X-ray emission from the tenu…
Isophotal Diameters of Galaxies at High Redshifts
Weedman, Daniel W.; Williams, Karen L.
New ultraviolet observations and archival spectra are presented for the bright disk of the galaxy NGC 4736 to derive the ultraviolet surface brightness profile. This is used to predict the appearance of such a galaxy at high redshift. The profiles in red light of 100 galaxies determined by S. Kent (1984) are used with assumed ultraviolet spectra t…