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X-ray map from the EXOSAT galactic plane survey and a direct demodulation technique.
Lu, F. J.; Li, T. P.; Page, C. G. +2 more
In 1984 the EXOSAT observatory scanned the galactic plane with its medium-energy array which had a spatial resolution of about 0.75deg. The data analysis used at that time was unable to resolve some of the more complex regions near the galactic centre. The direct demodulation method is a technique to solve the image reconstruction problem in high …
The empirical white dwarf mass-radius relation and its possible improvement by HIPPARCOS
Schmidt, H.
The famous mass-radius relation of white dwarf stars is based on theoretical considerations. The structure of a white dwarf, and thereby its fundamental properties, are deduced from the physical properties of the degenerate electron gas. Numerical computations take temperature and evolution effects into consideration. However, the few cases in whi…
Interstellar pickup H+ Ions at 8.3 AU: Pioneer 10 plasma and magnetic field analyses
Intriligator, Devrie S.; Siscoe, George L.; Miller, W. David
Analysis of Pioneer 10 plasma and magnetic field observations at 8.3 AU in 1975 provides new evidence for the presence of interstellar pickup hydrogen (H+) ions. Use of plasma sensors that look far from the solar wind direction confirms the spherical shell distribution of the pickup ions in velocity space. Phase space density and flux e…
CIV absorption from hot gas inside the supergiant shell LMC4 observed with HST and IUE.
Bomans, D. J.; de Boer, K. S.; Grebel, E. K. +1 more
High resolution ultraviolet spectra obtained with the HST-GHRS of two stars in the direction of the supergiant shell LMC4 unambiguously show absorption by substantial quantities of CIV gas at velocities near the the systemic velocity of the LMC. In combination with the detection of diffuse X-rays from the LMC4 by ROSAT and other supporting data, t…
On the nature of the UV turnup in early-type galaxies.
Alloin, D.; Pastoriza, M. G.; Bonatto, C. +1 more
We study the UV turnup in early-type galaxies from coadded IUE spectra reaching an unprecedented signal to noise ratio. Some spectral groups resulted with strong or moderate UV turnup, while in others it is very weak or absent. We study the relationships of the UV turnup intensity with absolute magnitude, X-ray and Hα luminosities. Galaxies in the…
ISO LWS measurement of the far-infrared spectrum of Saturn.
Ade, P. A. R.; Lellouch, E.; Encrenaz, T. +24 more
The spectrum of Saturn from 43 to 197µm was measured with the ISO Long Wavelength Spectrometer (LWS) during the performance verification phase of the mission. The measurements were made using the LWS in grating mode, with spectral resolutions of 0.29µm from 43 to 90µm and 0.6µm from 90 to 197µm. The spectrum was compa…
Hubble Space Telescope Observations of Planetary Nebulae in the Magellanic Clouds. III. Ultraviolet Spectroscopy Using the Faint Object Spectrograph
Ford, H. C.; Harrington, J. P.; Wood, P. R. +6 more
Ultraviolet grating spectra (λλ1150-2300) of planetary nebulae in the Magellanic Clouds, obtained with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST), are used to identify and measure nebular emission lines and continua, and in one case to detect the stellar wind of the central star. Eight nebulae are observed in the Large…
The White-Dwarf Companions of 56 Persei and HR 3643
Bergeron, Pierre; Simon, Theodore; Landsman, Wayne
We have obtained low-dispersion IUE spectra of the stars 56 Persei (F4 V) and HR 3643 (F7 II), as part of a survey of late-type stars with a 1565A flux excess in the TD-1 ultraviolet sky survey. The IUE spectrum of each star reveals the presence of a hot white dwarf companion. We fit the Ly-alpha profile and ultraviolet continuum using pure hydrog…
Hubble Space Telescope Planetary Camera Images of NGC 1316 (Fornax A)
Faber, S. M.; Grillmair, C. J.; Ajhar, E. A. +7 more
We present HST Planetary Camera V and I band images of the central region of the peculiar giant elliptical galaxy NGC 1316. These high resolution images reveal that the central surface brightness rises sharply to 12.1 mag arcsec^-2^ in the I band and 13.5 mag arcsec^-2^ in the V band. The inner profile is well fit by a nonisothermal core model wit…
The ISO/LWS spectrum of the EGG nebula, AFGL 2688.
Omont, A.; Ade, P. A. R.; Burgdorf, M. +35 more
We present an ISO Long Wavelength Spectrometer (LWS) grating spectrum of the carbon-rich proto-planetary nebula AFGL 2688 between 43 and 194µm. The far-infrared spectrum of AFGL 2688 is dominated by strong rotational transitions of CO which are detected from J=14-13 up to J=23-22. The atomic fine structure lines [O I] and [C II] are not dete…