Search Publications
The Winds of Hot Stars in External Galaxies. III. HST UV Spectroscopy of O and B Supergiants in M31 and M33
Massey, Philip; Hutchings, J. B.; Bianchi, Luciana
HST Faint Object Spectrograph (FOS) UV (1200-3300 A) spectra of nine late-O and early-B supergiants in M31, and one B1.5 supergiant in M33, are presented. The morphologies of the UV line spectra are discussed and compared with those of Galactic and Magellanic Cloud stars of similar optical spectral type. The UV spectral signatures of the M31 and M…
Ultraviolet ages of young clusters in the Magellanic Clouds.
Castellani, V.; Cassatella, A.; Brocato, E. +2 more
Following a previous investigation on the integrated UV colours of stellar clusters (Barbero et al. 1990), we study the calibration of the ultraviolet colour index C(15-31) in terms of cluster age, using observations by the International Ultraviolet Explorer of 29 young and populous clusters of the Large Magellanic Cloud (LMC), and of the Small Ma…
The gravitational lens CFRS14.1311 = HST 14176+5226.
Lilly, S. J.; Hammer, F.; Crampton, D. +1 more
Ratnatunga et al. (1995) have recently proposed that an object, HST 14176+5226, in the "Groth-Westphal" HST survey strip is an "Einstein cross" gravitational lens. By chance, this object has been previously observed in the Canada-France Redshift Survey. The candidate lens catalogued as CFRS14.1311, is an elliptical galaxy at z=0.81. In addition, t…
Hubble Space Telescope Imaging of Bright Galactic X-Ray Binaries in Crowded Fields
Anderson, Scott F.; Wachter, Stefanie; Margon, Bruce +1 more
We report high spatial resolution HST imagery and photometry of three well-studied, intense Galactic X-ray binaries, X2129 +470, CAL 87, and GX 17 +2. All three sources exhibit important anomalies that are not readily interpreted by conventional models. Each source also lies in a severely crowded field, and in all cases the anomalies would be remo…
The Discovery of an Erupting Dwarf Nova in NGC 6624
Zurek, David R.; Rich, R. Michael; Shara, Michael M.
The core of the globular cluster NGC 6624 has been imaged with the Hubble Space Telescope at three separate epochs. We report the detection of a dwarf nova in eruption at a distance of 5 core radii from the center of the cluster---one of the densest in the Galaxy. This is only the fourth dwarf nova detected in a globular cluster. Our temporal cove…
Stochastic Wave Growth, Power Balance, and Beam Evolution in Type III Solar Radio Sources
Robinson, P. A.
Energy-balance arguments are combined with the stochastic-growth theory of type III radio sources to determine the properties of the source in average dynamical equilibrium with the beam, and the beam's long-term evolution. Purely linear stochastic-growth theory has previously emphasized that the beam evolves to a state close to marginal stability…
UV Studies and the Solar Wind
Bertaux, J. L.; Lallement, R.; Quemeelais, E.
The solar wind carves a cavity in the flow of interstellar H atoms through the solar system by charge-exchange ionization. The resulting Ly-α sky pattern depends on the latitude distribution of the solar wind flux and velocity. We review how the solar wind characteristics (mass flux latitude distribution) can be retrieved from Ly-α observations, y…
The 0.8 Day Orbit of the Precataclysmic Binary EUVE J1016-053
Thorstensen, John R.; Bowyer, Stuart; Vennes, Stephane
The optical counterpart of the new extreme ultraviolet source EUVE J1016-053 (= RE 1016-053) is known to show intermittent sharp Balmer and He I emission and traces of an M dwarf associated with a white dwarf optical spectrum. We present extensive optical spectroscopy showing the emission lines vary in velocity and intensity on a period of 0°.7892…
An overview of the anisotropy telescope observations of MeV ions during the Ulysses Jupiter encounter
Balogh, A.; Forsyth, R. J.; Cowley, S. W. H. +4 more
Observations of ∼ MeV ions obtained in Jupiter's magnetosphere with the COSPIN Anisotropy Telescope experiment during Ulysses' encounter with Jupiter in February 1992 are presented. Ulysses is the fifth spacecraft to have visited Jupiter's magnetosphere, all of which approached Jupiter from the mid-morning sector close to the equatorial plane. Uly…
The variable mass loss of the peculiar supergiant P Cygni.
Sterken, C.; Israelian, G.; Parker, J. W. +1 more
The study of iron lines from 49 high-resolution IUE spectra observed in the period of 1985-1991 allowed us to find a repetition time between two successive shells of the order of six months. We found that absorption lines of Fe III often have two components while Fe II lines can have three. P Cygni is the only luminous blue variable that does not …