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Ultraviolet to Near-Infrared Spectral Distributions of Star-forming and Seyfert 2 Galaxies
Storchi-Bergmann, Thaisa; Challis, Peter; Kinney, Anne L.
Combined UV, optical and near-IR spectral distributions of a sample of 48 southern star-forming and Seyfert 2 galaxies are presented. The optical and near-IR spectra were obtained using apertures matching those of the UV observations (10" X 20") and in most cases correspond to the bulk of the gas and stellar population contribution from the whole …
Determination of the Hubble constant from observations of Cepheid variables in the galaxy M96
Ferguson, H. C.; Tanvir, N. R.; Shanks, T. +1 more
New Hubble Space Telescope observations of Cepheid variable stars in the nearby galaxy M96 give a distance to the host galaxy group, Leo I, of 11.6 +/- 0.8 Mpc. This value, used in conjunction with several reliable secondary indicators of relative distance, constrains the distances to more remote galaxy clusters, and yields a value of the Hubble c…
Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
Duflot, M.; Figon, P.; Meyssonnier, N.
We give a common version of the two catalogues of Mean Radial Velocities by Wilson (1963) and Evans (1978) to which we have added the catalogue of spectroscopic binary systems (Batten et al. 1989). For each star, when possible, we give: 1) an acronym to enter SIMBAD (Set of Identifications Measurements and Bibliography for Astronomical Data) of th…
The Size Distribution of Interstellar Dust Particles as Determined from Polarization: Spheroids
Martin, P. G.; Kim, Sang-Hee
We have determined the size distribution of polarizing interstellar dust grains based on electromagnetic scattering by spheroidal particles, extending our original work based on infinite cylinders. Shapes and alignment variants included the following: perfectly aligned oblate particles with axial ratios 1.414:1, 2:1, 4:1, and 6:1, picket fence pro…
Ulysses observations of the radial magnetic field
Balogh, A.; Smith, Edward J.
The radial component of the magnetic field in the southern hemisphere has been measured at Ulysses as it traveled from the equator to -80.2° latitude and returned. The radial component multiplied by the square of the radial distance, i.e., BRr2, averaged over 77 day intervals (three solar rotations) is approximately constant …
Discovery of Cepheids in NGC 5253: Absolute Peak Brightness of SN IA 1895B and SN IA 1972E and the Value of H 0
Panagia, N.; Saha, A.; Labhardt, Lukas +4 more
Observations with the Hubble Space Telescope between 1993 May 31 and 1993 July 19 in 20 epochs in the F555W passband and five epochs in the F785LP passband have led to the discovery of 14 Cepheids in the Amorphous galaxy NGC 5253. The apparent V distance modulus is (m - M)_AV_ = 28.08 +/- 0.10 determined from the 12 Cepheids with normal amplitudes…
D/H and O-18/O-16 ratio in the hydronium ion and in neutral water from in situ ion measurements in comet Halley
Altwegg, K.; Balsiger, H.; Geiss, J.
The D/H ratio and the O-18/O-16 ratio in hydronium ions in the gas coma of comet Halley have been determined from ion data obtained by the high intensity sensor (HIS) of the ion spectometer (IMS) on board the spacecraft Giotto in 1986. The HIS instrument measured the reliable data for the water group ions over a large distance range from the nucle…
Atlas of Synthetic Ultraviolet Spectra of Massive Star Populations
Robert, Carmelle; Heckman, Timothy M.; Leitherer, Claus
An atlas of synthetic ultraviolet spectra of a population of massive stars is presented. The spectra are based on a stellar library of lUE high-dispersion spectra of O and Wolf-Rayet stars, coupled to an evolutionary synthesis code. Later spectral types are included via low-dispersion spectra. Line profiles of N V λ1240, Si IV λ1400, C IV λ1550, H…
Testing Unified X-Ray/Ultraviolet Absorber Models with NGC 5548
Elvis, Martin; Mathur, Smita; Wilkes, Belinda
The bright Seyfert galaxy NGC 5548 shows absorption features in its X-ray and UV spectra. The large amount of optical/UV and X-ray monitoring data available for this object makes it an ideal candidate to test our model of a common X-ray/UV absorber. We show that the X-ray/UV absorption is caused by a highly ionized (2.2 < U < 2.8), high colu…
The Large-Scale Structure of the Heliospheric Current Sheet During the ULYSSES Epoch
Hoeksema, J. Todd
Ulysses is traversing the Sun's polar regions for the first time a year or two before solar minimum. If the heliospheric magnetic field behaves as we expect, the heliospheric current sheet (HCS) during this stage of the sunspot cycle should be quite stable and lie nearly flat, close to the equator. The high latitude solar fields should be unipolar…