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Kinematics of the local universe. VI. B-band Tully-Fisher relation and mean surface brightness
Theureau, G.
Continuing our study of the type dependence of the TF relation, we present a new attempt to reduce the scatter of that relation by using the observed mean surface brightness Sigma of galaxies. It is shown that the zero-point of the relation is a continuous function of Sigma , well described by a third or fourth degree polynome. Taking this effect …
The Eclipsing Supersoft X-Ray Binary CAL 87
Hutchings, J. B.; Crampton, D.; Cowley, A. P. +1 more
We present and discuss 25 spectra obtained in 1996 November, covering all phases of the CAL 87 binary system. These spectra are superior both in signal-to-noise ratio and wavelength coverage to previously published data, so additional spectral features can be measured. Photometry obtained on the same nights is used to confirm the ephemeris and for…
WFPC2 Observations of the Small Magellanic Cloud Intermediate-Age Populous Cluster NGC 416
Sarajedini, Ata; Mighell, Kenneth J.; French, Rica S.
We present our analysis of archival Hubble Space Telescope Wide Field Planetary Camera 2 observations in F555W (~V) and F450W (~B) of the intermediate-age populous star cluster NGC 416 in the Small Magellanic Cloud (SMC). We use published photometry of two other SMC populous star clusters, Lindsay 1 and Lindsay 113, to investigate the age sequence…
The Ultraviolet Albedo of Titan
Smith, T. Ed; Feldman, Paul D.; Strobel, Darrell F. +2 more
Ultraviolet spectra of Titan obtained with the Faint Object Spectrograph of the Hubble Space Telescope in October 1991 and August 1992 have yielded a disk-average geometric albedo of 0.02-0.044 from 1800-3300 Å. These results are in excellent agreement with previous UV measurements from 2200-3300 Å spanning two decades, but have a significantly hi…
Latitudinal distribution of >106MeV protons and its relation to the ambient solar wind in the inner southern and northern heliosphere: Ulysses Cosmic and Solar Particle Investigation Kiel Electron Telescope results
Sierks, H.; Kunow, H.; Bothmer, V. +12 more
We present observations and model calculations of the modulated intensities of galactic cosmic ray protons above 106 MeV/n along the Ulysses trajectory. Data are taken by the Cosmic and Solar Particle Investigation (COSPIN) Kiel Electron Telescope (KET) from spring 1993 to fall 1996. During this time period solar activity decreased and galactic co…
On the Unresolved Fine Structures of the Solar Atmosphere. III. Elemental Abundances Consideration
Feldman, Uri
Results from high-quality solar upper atmosphere observations in the 104-106 K range contradict predictions made by models that assume that a single class of structures stretching throughout the entire temperature domain, from the cold chromosphere to the hot corona, is responsible for all the radiation we see. As a result, I…
Possible High-Redshift, Low-Luminosity Active Galactic Nuclei in the Hubble Deep Field
MacAlpine, Gordon M.; Jarvis, R. Michael
In the Hubble Deep Field (HDF), 12 candidate sources of high-redshift (z > 3.5) active galactic nuclei (AGN) have been identified. The color selection criteria were established by passing spectra of selected quasars and Seyfert galaxies (appropriately redshifted and modified for ``Lyman forest'' absorption), as well as stars, observed normal an…
Observations of QSO J2233-606 in the Southern Hubble Deep Field
Webb, J. K.; Drinkwater, M. J.; Sealey, K. M.
The Hubble Deep Field South (HDF-S) Hubble Space Telescope (HST) observations are expected to begin in 1998 October. We present a composite spectrum of the QSO in the HDF-S field covering UV/optical/near-IR wavelengths, obtained by combining data from the Australian National University 2.3 m telescope with STIS on the HST.1 This intermediate-resol…
ISOCAM Molecular Hydrogen Images of the Cepheus E Outflow
Garnavich, Peter M.; Molinari, Sergio; Noriega-Crespo, Alberto
The physical characteristics of the Cepheus E ``embedded'' outflow are analyzed using ISOCAM images in the v = 0-0 S(5) 6.91 µm and S(3) 9.66 µm molecular hydrogen lines. We find that the morphology of the Cep E outflow in the ground vibrational H_2 lines is similar to that in the near-infrared v = 1-0 2.12 µm line. At these mid-…
Morphological Changes, Evidence for a Collimating Disk, and Extremely Young Jetlike Components in the Planetary Nebula IC 4997
Miranda, Luis F.; Torrelles, José M.
We present VLA-A radio continuum observations at 3.6 cm and 2 cm of the extremely young, double-shell planetary nebula IC 4997. A comparison of the new 3.6 cm map with that obtained in 1995 July shows that morphological changes have occurred in the nebula in ~=1.3 yr. These changes reveal themselves by the presence in the outer shell of several ne…