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Ulysses high-latitude observations of ions accelerated by co-rotating interaction regions
Balogh, A.; Forsyth, R. J.; Goldstein, B. E. +3 more
We present observations of energetic ions (E∼1 MeV) from the Ulysses spacecraft during its first pass from the ecliptic plane to the southern high-latitude regions of the heliosphere. At latitudes less than ∼13°S Ulysses was completely immersed in the heliomagnetic streamer belt, and observed a ∼1 MeV proton intensity which showed little evidence …
Hubble Space Telescope Images of The Seyfert Galaxies NGC 5929 And MCG 8-11-11
Heckman, Timothy M.; Mulchaey, John S.; Bower, Gary A. +3 more
We present the initial results of a program to obtain high resolution images of Seyfert galaxies with the Planetary Camera aboard the Hubble Space Telescope. In this paper we discuss the images of the type 2 Seyfert NGC 5929 and the type 1.5 Seyfert MCG 8-11-11 (=UGC 3374). The images were obtained in the emission lines of [O III] λλ4959,5007 and …
Far-Ultraviolet Photometry of the Globular Cluster Omega CEN
O'Connell, R. W.; Bohlin, R. C.; Stecher, T. P. +9 more
We present far-ultraviolet images of the globular cluster omega Centauri obtained with the Ultraviolet Imaging Telescope (UIT) during the 1990 December Astro-1 mission. A total of 1957 sources are detected at 1620 A to a limiting ultraviolet (UV) magnitude of 16.4 in the central 24 min diameter region of the field and a limit of 15.6 over the rema…
HST Imaging of Quasi-stellar Objects with WFPC2
Holtzman, Jon; Sparks, W. B.; Hutchings, J. B. +3 more
Early images were taken with the optically corrected WFPC2 camera of the Hubble Space Telescope of the low-redshift QSOs 1229+204 and 2141+175, which are radio-quiet and radio-loud, respectively. We discuss image restoration on the data. The objects were chosen on the basis of structure seen with 0.5" resolution with the CFHT high-resolution camer…
Spectral analysis of the hottest known helium-rich white dwarf: KPD0005+5106.
Werner, K.; Heber, U.; Fleming, T.
We present a non-LTE model atmosphere analysis of the helium-rich white dwarf KPD0005+5106. The analysis is based on optical spectra obtained at the Calar Alto 3.5m telescope, ultraviolet observations retrieved from the Hubble Space Telescope data archive, and X-ray data recorded during the ROSAT all-sky survey. From the optical and ultraviolet He…
X-Ray Emission from a Simulated Cluster of Galaxies
Katz, Neal; Tsai, John C.; Bertschinger, Edmund
Using the 1993 cluster simulation of Katz & White, we analyze the intracluster medium and investigate the accuracy of the standard hydrostatic method for determining cluster masses. We show that the simulated cluster gas is in hydrostatic equilibrium with a subsonic flow toward the center. Inside a radius of ∼100 kpc, this flow is in a steady …
Removing Cosmic-Ray Hits from Multi-Orbit HST Wide Field Camera Images
Windhorst, Rogier A.; Franklin, Barbara E.; Neuschaefer, Lyman W.
We present an optimized algorithm that removes cosmic rays ("CRs") from multi-orbit HST Wide Field/Planetary Camera ("WF/PC") images. It computes the image noise in every iteration from the WF/PC CCD equation. This includes all known sources of random and systematic calibration errors. We test this algorithm on WF/PC stacks of 2-12 orbits as a fun…
High time resolution observations of Cygnus X-3 with EXOSAT.
van der Klis, M.; Berger, M.
We have studied the fast timing behaviour of Cygnus X-3 using the entire EXOSAT ME dataset on this source, consisting of 22 observations that cover a total of 320000seconds. This large amount of data allowed us to measure the rapid (>1Hz) X-ray variability of the source to an unprecedented accuracy of 0.2% fractional rms amplitude. Above 256Hz,…
The Nuclear Regions of NGC 3311 and NGC 7768 Imaged With the Hubble Space Telescope Planetary Camera
Lauer, Tod R.; Faber, S. M.; Grillmair, Carl J. +4 more
We present high-resolution, V band images of the central regions of the brightest cluster ellipticals NGC 3311 and NGC 7768 taken with the Planetary Camera of the Hubble Space Telescope. The nuclei of both galaxies are found to be obscured by dust, though the morphology of the dust is quite different in the two cases. The dust cloud which obscures…
Ultraviolet Interstellar Absorption Line in the LMC: Searching for Hidden SNRs
Chu, Y. -H.; Wakker, B.; Mac Low, M. -M. +1 more
Strong x-ray emission detected in Large Magellanic Cloud (LMC) superbubbles has been explained as the result of interior supernova remnants (SNRs) hitting the dense superbubble shell. Such SNRs cannot be found using conventional criteria. We thus investigate the possibility of using the interstellar absorption properties in the UV as a diagnostic …