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On Quasar Masses and Quasar Host Galaxies
Laor, Ari
The mass of massive black holes in quasar cores can be deduced by using the typical velocities of Hβ-emitting clouds in the broad-line region and by the size of this region. However, this estimate depends on various assumptions and is susceptible to large systematic errors. The Hβ-deduced black hole mass in a sample of 14 bright quasars is found h…
Classical monopoles: Newton, NUT space, gravomagnetic lensing, and atomic spectra
Lynden-Bell, D.; Nouri-Zonoz, M.
This article reviews the dynamics and observational signatures of particles interacting with monopoles, beginning with a scholium in Newton'sPrincipia. The orbits of particles in the field of a gravomagnetic monopole, the gravitational analog of a magnetic monopole, lie on cones; when the cones are slit open and flattened, the orbits are the ellip…
Observations of Correlated White-Light and Extreme-Ultraviolet Jets from Polar Coronal Holes
Llebaria, A.; St. Cyr, O. C.; Michels, D. J. +7 more
Time-lapse sequences of white-light images recorded with the Large Angle Spectrometric Coronagraph (LASCO) on the Solar and Heliospheric Observatory (SOHO) frequently show long, narrow structures moving outward over the Sun's polar regions at high apparent speeds. By comparing the LASCO observations with Fe XII λ195 spectroheliograms made with the…
HIPPARCOS observations of pre-main-sequence stars
Bastian, U.; Krautter, J.; Rucinski, S. M. +2 more
We present first results of Hipparcos observations of nearby low-mass pre-main-sequence (PMS) stars (TTauri and Herbig Ae/Be stars). The data obtained by Hipparcos allow us to derive weighted mean parallaxes for three major nearby star-forming regions (SFRs), Lupus, Chamaeleon I and Taurus-Auriga. Furthermore, results on the isolated objects AB Do…
Active Volcanism on Io as Seen by Galileo SSI
Geissler, Paul; Belton, Michael J. S.; Carr, Michael H. +11 more
Active volcanism on Io has been monitored during the nominal Galileo satellite tour from mid 1996 through late 1997. The Solid State Imaging (SSI) experiment was able to observe many manifestations of this active volcanism, including (1) changes in the color and albedo of the surface, (2) active airborne plumes, and (3) glowing vents seen in eclip…
HST, radio and infrared observations of 28 3CR radio galaxies at redshift z~1 - II. Old stellar populations in central cluster galaxies
Best, P. N.; Longair, M. S.; Roettgering, H. J. A.
Hubble Space Telescope images of 3CR radio galaxies at redshifts 0.6<z<1.8 have shown a remarkable variety of structures, generally aligned along the radio axis, indicating that the radio source strongly influences the optical appearance of these galaxies. In this paper we investigate the host galaxies underlying this aligned emission, combi…
Broadening of SI VIII lines observed in the solar polar coronal holes
Doyle, J. G.; Wilhelm, K.; Teriaca, L. +1 more
We study the variation of the line width and electron density as a function of height above two coronal holes from forbidden spectral lines of Si viii. The spectra were obtained with the Solar Ultraviolet Measurements of Emitted Radiation spectrometer flown on the Solar and Heliospheric Observatory spacecraft. The observations concentrate on the d…
Mixing processes during the evolution of red giants with moderate metal deficiencies: the role of molecular-weight barriers
Wallerstein, George; Charbonnel, Corinne; Brown, Jeffery A.
We have assembled accurate abundance data for Li, C, and N as well as the (12}C/({13)) C ratio for five field giants with [Fe/H] =~ - 0.6 including Arcturus and two stars in the globular cluster 47 Tuc. Using their very precise Mbol values obtained from HIPPARCOS parallaxes, we can place them into an evolutionary sequence. The sequence …
The Gaseous Extent of Galaxies and the Origin of Lyα Absorption Systems. III. Hubble Space Telescope Imaging of Lyα-absorbing Galaxies at z < 1
Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Webb, John K. +1 more
We present initial results of a program to obtain and analyze Hubble Space Telescope (HST) Wide Field Planetary Camera 2 images of galaxies identified in an imaging and spectroscopic survey of faint galaxies in fields of HST spectroscopic target QSOs. We measure properties of 87 galaxies, of which 33 are associated with corresponding Lyα absorptio…
The Effect of Temperature Anisotropy on Observations of Doppler Dimming and Pumping in the Inner Corona
Li, Xing; Habbal, Shadia Rifai; Kohl, John L. +1 more
Recent observations of the spectral line profiles and intensity ratio of the O VI λλ1032 and 1037.6 doublet by the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO), made in coronal holes below 3.5 RS, provide evidence for Doppler dimming of the O VI λ1037.6 line and pumping by the chromospheri…