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Observations and models of the UV/soft X-ray spectrum of the quasar PG 1116+215.
Molendi, S.; Ulrich, M. -H.
The radio quiet quasar PG 1116+215 has been observed four times with the ROSAT-PSPC, once during the All-Sky Survey and three times in pointed observations including one lasting 24320 seconds (25300 counts). Contemporaneous IUE observations were secured for two of the pointed observations. Overall the PSPC spectra at all 4 epochs can be reasonably…
Acceleration of solar wind ions by oblique interplanetary shocks
Forsyth, R.; Baring, M. G.; Ogilvie, K. W. +1 more
This paper compares observations of proton distributions made by the SWICS ion mass spectrometer on Ulysses at nearby interplanetary shocks with Monte Carlo simulations of particle acceleration at oblique collisionless shocks. The shock parameters are obtained from upstream measurements of the solar wind and magnetic field, and the input particles…
Extragalactic symbiotic systems. II. Hubble Space Telescope observations of S 63 and Linsay 358.
Vogel, M.; Nussbaumer, H.
We present ultraviolet spectra of two symbiotic systems in the Magellanic Clouds obtained with the Faint Object Spectrograph onboard the refurbished Hubble Space Telescope. Because of the known distances to the LMC and SMC, and because of the high sensitivity of HST, accurate luminosities and radiation temperatures of the hot radiation source in S…
Duplicity amongst HIPPARCOS stars.
Tucholke, H. -J.; Brosche, P.; Odenkirchen, M.
Stars observed by the astrometry satellite Hipparcos may be unknown double stars. A subsample of those are dangerous for the extragalactic link of Hipparcos proper motions by long-term photographic proper motions, if the time base of Hipparcos is too short to detect the orbital motion. The probability of these cases and the typical size of the pho…
Far-Ultraviolet Spectrum of Fairall 9 with the Hopkins Ultraviolet Telescope
Kriss, Gerard A.; Zheng, Wei; Davidsen, Arthur F. +1 more
We observed the Seyfert 1 galaxy Fairall 9 with the Hopkins Ultraviolet Telescope (HUT) for ~3500 s during the Astro-2 mission. The spectrum covers 820--1840 A with a resolution of ~3 A. The intrinsic far-UV continuum is unattenuated to wavelengths as short as 920 A (~880 A in the galaxy's rest frame) and can be fitted with a power law with f nu ~…
HIPPARCOS minor planets: first step towards the link between the HIPPARCOS and the dynamical reference frames.
Bec-Borsenberger, A.; Bange, J. -F.; Bougeard, M. -L.
The observations of minor planets are of particular interest for determining a possible rotation between the Hipparcos and the dynamical reference frames. In order to evaluate these unknowns, Hipparcos data are compared to the values calculated from the equations of motion. The satellite's observations are related to intermediate reference frames …
Particle events associated with local type III radio emission and Langmuir waves in the interplanetary medium.
Chaizy, P.; Pick, M.; Reiner, M. +3 more
The first detection of local type III radio emissions at the fundamental and harmonic of the plasma frequency was made by the Ulysses spacecraft when it was in the ecliptic plane and between ~1.4 and ~2.2AU from the Sun. In-situ Langmuir waves were observed simultaneously with each local radio event, indicating the presence of an electron beam at …
Detection, Photometry, and Completeness of FOCAS Catalogs for the HST Medium-Deep Survey
Valdes, Francisco; Griffiths, Richard E.; Neuschaefer, Lyman +1 more
We discuss the methods which we have developed and applied to optimize the detection efficiency of faint galaxies with the HST Wide Field and Planetary Cameras both prior and subsequent to the HST refurbishment mission in December 1993. Our methods are based on the FOCAS (Tyson and Jarvis 1979) automated detection software package, which we have a…
ULYSSES Observations of Cosmic Gamma-Ray Bursts
Cline, T.; Hurley, K.; Sommer, M. +2 more
We review the current status of the Ulysses mission and summarize the results to date of the GRB experiment. This instrument detects bursts at the rate of about one every 3.5 days, and the localization data are being disseminated rapidly via the BACO-DINE and NMSU networks. The mission should operate through 2001, and future missions to Mars start…
The ultraviolet spectrum of η Carinae. II. 1980 IUE observations of the Homunculus.
Baratta, G. B.; Viotti, R.; Cassatella, A.
We analyze the ultraviolet observations of the circumstellar nebula of η Car (the Homunculus) obtained in December 1980 with IUE. A high resolution spectrum was obtained with the IUE large aperture from 6" to 17" NW of η Car, near the H condensation (the head). The measured flux appears two orders of magnitude larger than that expected from the in…