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Analysis of the Photospheric Epoch Spectra of Type IA Supernovae SN 1990N and SN 1991T
Kirshner, Robert P.; Leibundgut, Bruno; Sonneborn, George +3 more
An analysis of the photospheric epoch optical and UV spectra (obtained with the IUE satellite) of Type Ia supernovae SN 1990N and SN 1991T is presented. To perform the analysis, synthetic spectra calculated using an LTE radiative transfer procedure and white dwarf explosion models of Type Ia supernovae were fitted to the observations. For both sup…
Magnetic Field Observations During the Ulysses Flyby of Jupiter
Dougherty, M. K.; Balogh, A.; Tsurutani, B. T. +5 more
The Jovian flyby of the Ulysses spacecraft presented the opportunity to confirm and complement the findings of the four previous missions that investigated the structure and dynamics of the Jovian magnetosphere and magnetic field, as well as to explore for the first time the high-latitude dusk side of the magnetosphere and its boundary regions. In…
The ULYSSES dust experiment
Kissel, J.; Morfill, G. E.; Gruen, E. +7 more
The Ulysses dust experiment is intended to provide direct observations of dust grains with masses between 10 exp -16 g and 10 exp -6 g in interplanetary space, to investigate their physical and dynamical properties as functions of heliocentric distance and ecliptic latitude. Of special interest is the question of what portion is provided by comets…
0.7- to 23-µm photometric observations of P/Halley 1986 III and six recent bright comets
Gehrz, R. D.; Ney, E. P.
We report 0.7- to 23-µm observations of P/Halley 1986 III and six other recent bright comets. P/Halley was measured on 47 occasions between 1985 December 12 UT and 1986 May 6 UT, several times within hours of the perihelion passage on 1986 February 9 UT. Our data show that the strength of the 10-µm silicate emission feature and the tem…
Planetary Camera Observations of the M87 Stellar CUSP
Schneider, Donald P.; Lauer, Tod R.; Faber, S. M. +11 more
Analysis of V and I band HST Planetary Camera images of the giant elliptical galaxy M87 show that its central starlight distribution is consistent with the black hole M_black hole_ = 2.6 X 10^9^ M_sun_ cusp model proposed for M87 by Young et al, [ApJ, 221,721(1978)]. A combined approach of image deconvolution and modeling is used to investigate th…
Errors Associated with Fitting Gaussian Profiles to Noisy Emission-Line Spectra
Ayres, Thomas R.; Lenz, Dawn D.
Landman, Roussel-Dupre, and Tanigawa developed prescriptions to predict profile fitting errors for Gaussian emission lines perturbed by white noise. We show that their scaling laws can be generalized to more complicated signal-dependent "noise models" of common astronomical detector systems. (SECTION: Instrumentation and Data Analysis)
The spectral signature of the cooling flow in Abell 478.
Fabian, A. C.; Edge, A. C.; Johnstone, R. M. +1 more
We present X-ray spectra of Abell 478 taken with the Ginga LAC and with the Einstein SSS. The LAC data set an upper limit of ~440 M_sun_ yr^-1^ on the mass deposition rate throughout the whole cluster if a value for the galactic absorption based on 21-cm observations of H I is adopted. The SSS data strongly require an absorbing column density well…
A Multiwavelength Study of the Supernova Remnant N49 in the Large Magellanic Cloud
Blair, William P.; Raymond, John C.; Long, Knox S. +1 more
Using the 2.5 m du Pont telescope at Las Campanas, the International Ultraviolet Explorer satellite, and archival high-resolution imager X-ray data from the Einstein Observatory, we present a detailed imaging and spectroscopic study of the supernova remnant (SNR) N49 in the Large Magellanic Cloud. Although the X-ray and optical morphology of N49 a…
Spectral Synthesis in the Ultraviolet. IV. A Library of Mean Stellar Groups
O'Connell, Robert W.; Burstein, David; Wu, Chi-Chao +1 more
A library of mean UV stellar energy distributions is derived from IUE spectrophotometry of 218 stars. The spectra cover 1230-3200 A with a spectral resolution of about 6 A. They have been corrected for interstellar extinction and converted to a common flux and wavelength scale. Individual stars were combined into standard groups according to their…
Ulysses Radio and Plasma Wave Observations in the Jupiter Environment
Goetz, K.; Kellogg, P. J.; MacDowall, R. J. +23 more
The Unified Radio and Plasma Wave (URAP) experiment has produced new observations of the Jupiter environment, owing to the unique capabilities of the instrument and the traversal of high Jovian latitudes. Broad-band continuum radio emission from Jupiter and in situ plasma waves have proved valuable in delineating the magnetospheric boundaries. Sim…