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LY alpha Emission from Cooling Flows and Measures of the Dust Content of Rich Clusters of Galaxies
Hu, Esther M.
We tabulate Ly α and UV continuum fluxes from measurements across the emission-line regions of 10 "cooling flow" clusters of galaxies. Comparison of Ly α emission fluxes obtained with the IUE satellite with optical Balmer emission fluxes is used to demonstrate that the lines of sight to the centers of these clusters show an average excess reddenin…
Hubble Space Telescope Wide Field Camera Imaging of the Gravitational Lens 2237+0305
Schneider, Donald P.; Rix, Hans-Walter; Bahcall, John N.
Hubble Space Telescope Wide Field Camera images of the gravitational lens 2237+0305 in the F336W ("U") and F702W ("A") filters are used to construct models of the system. Positions for the four quasar images, accurate to +/-0.015", and relative magnitudes in U and R, accurate to +/-0.06 and 0.04 mag respectively, are determined. The upper limits o…
The O/C abundance ratio in absorbing gas clouds at high redshift
Clavel, J.; Reimers, D.; Vogel, S. +5 more
THE intrinsic extreme ultraviolet (EUV) spectrum of quasars, in which spectral lines of He and CNO ions should appear, is in most cases strongly absorbed by the hydrogen Lyman continuum of intergalactic matter at cosmological distances. The bright quasar HS1700 + 6416 (at redshift z = 2.72), from the Hamburg survey1, is a fortuitous exc…
Hubble Space Telescope Faint Object Spectrograph and Ground-based Observations of the Broad Absorption Line Quasar 0226-1024
Turnshek, David A.; Burbidge, E. M.; Morris, Simon L. +6 more
Faint Object spectrograph data from the Hubble Space Telescope of the broad absorption line quasar 0226 - 1024 have revealed the presence of 8-10 absorbing ions between 680 and 1000 A (restframe): C III, N III, N IV, O III, O IV, O VI, S V, S VI, possibly Ne VIII, and possibly O V^*^ arising from a metastable excited state. We also present ground-…
Orbital elements of S stars : revisiting the evolutionary status of S stars.
Jorissen, A.; Mayor, M.
The hypothesis of an evolutionary link between barium stars and the non-Mira S stars is discussed. The hypothesis of an evolutionary link between the barium stars and the non-Mira S stars is confirmed. The mass function distribution of S stars, indicating that the companions are likely white dwarfs, as is the case for barium stars, supports this h…
On the Nature of the Symbiotic Binary AX Persei
Mikolajewska, Joanna; Kenyon, Scott J.
Photometric and spectroscopic observations of the symbiotic binary AX Persei are presented. This system contains a red giant that fills its tidal lobe and transfers material into an accretion disk surrounding a low-mass main-sequence star. The stellar masses - 1 solar mass for the red giant and about 0.4 solar mass for the companion - suggest AX P…
Nonlinear magnetosonic waves and mirror mode structures in the March 1991 Ulysses interplanetary event
Tsurutani, Bruce T.; Smith, Edward J.; Balogh, Andre +1 more
In examining the March 23-25, 1991 Ulysses (2.2 AU) high speed solar wind events, we find two distinct plasma wave modes: steepened magnetosonic waves with whistler precursors and mirror mode structures. These two modes are locally generated by plasma instabilities, presumably associated with anisotropies existing in the energetic shock particles …
A Prediction of the gamma -Ray Flux from Nova Herculis 1991
Truran, James W.; Shore, Steven N.; Sonneborn, George +3 more
UV observations made with the IUE satellite of Nova Her 1991 are presented and discussed. A distance of 3.4 kpc and reddening of 0.6 E(B-V) to Nova Her 1991 are determined by comparing its UV and optical outburst behavior with those of the extragalactic ONeMg nova LMC 1990 No. 1. Her 1991 was also detected by Rosat five days into its outburst, and…
The Nature of the Recurrent Nova T Coronae Borealis: Ultraviolet Evidence for a White Dwarf Accretor
Cassatella, Angelo; Gilmozzi, Roberto; Selvelli, Pier L.
Data from eleven years of IUE observations of T CrB during its quiescent phase suggest that a white dwarf accretor rather than a main-sequence star is the hot component of the system. The spectroscopic and photometric behavior of T CrB during the 1946 outburst actually supports the interpretation of a thermonuclear runaway event on a massive white…
Evolving, Dynamical Models for Collapsed-Core Globular Clusters: M15 and NGC 6624
Cohn, Haldan N.; Lugger, Phyllis M.; Murphy, Brian W. +1 more
The stellar populations of the collapsed-core globular clusters M15 and NGC 6624 are investigated by fitting observed surface-brightness and projected velocity-dispersion profiles. The present evolving cluster models were generated by the direct Fokker-Planck method and incorporate realistic stellar mass spectra and energy input from binaries form…