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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…
The O II Luminosity Density of the Universe
Hogg, David W.; Cohen, Judith G.; Blandford, Roger +1 more
Equivalent widths of [O II] 3727 Å lines are measured in 375 faint galaxy spectra taken as part of the Caltech Faint Galaxy Redshift Survey centered on the Hubble Deep Field. The sensitivity of the survey spectra to the [O II] line is computed as a function of magnitude, color, and redshift. The luminosity function of galaxies in the [O II] line, …
Infrared Space Observatory Measurements of a [C II] 158 Micron Line Deficit in Ultraluminous Infrared Galaxies
Wolfire, M. G.; Lord, S. D.; Stacey, G. J. +6 more
We report measurements of the [C II] 157.74 µm fine-structure line in a sample of seven ultraluminous infrared galaxies (ULIGs) (LIR>1012 Lsolar) with the Long Wavelength Spectrometer on the Infrared Space Observatory. The [C II] line is an important coolant in galaxies and arises in interstellar gas expos…
An analytic solar magnetic field model
McKenzie, J. F.; Banaszkiewicz, M.; Axford, W. I.
We describe a simple analytic model for the magnetic field in the solar corona and interplanetary space which is appropriate to solar minimum conditions. The model combines an azimuthal current sheet in the equatorial plane with an axisymmetric multipole field representing the internal magnetic field of the Sun. The radial component of the field f…
The Hubble Space Telescope Quasar Absorption Line Key Project. XIV. The Evolution of Lyα Absorption Lines in the Redshift Interval z = 0-1.5
Turnshek, David A.; Schneider, Donald P.; Savage, Blair D. +10 more
We present the results of an analysis of the rate of evolution of the Lyα absorption lines in the redshift interval 0.0 to ~1.5 based upon a sample of 987 Lyα absorption lines identified in the spectra of 63 QSOs obtained with the Faint Object Spectrograph (FOS) of the Hubble Space Telescope (HST). These spectra were obtained as part of the QSO Ab…