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Bipolar and Multipolar Jets in Protoplanetary and Planetary Nebulae
Sahai, R.
One of the most exciting challenges facing theories of post-main sequence evolution today is to understand how Asymptotic Giant Branch (AGB) stars and their round circumstellar envelopes (CSEs) transform themselves into planetary nebulae (PNe) with their dazzling variety of aspherical morphologies. The most succesful model for shaping PNe--the ``g…
Ultraviolet Imaging Polarimetry of the Peculiar Seyfert 2 Galaxy Markarian 477
Cohen, Ross D.; Antonucci, Robert; Kishimoto, Makoto +3 more
We present the results of UV imaging polarimetry of the Seyfert 2 galaxy Mrk 477 taken by the Faint Object Camera on board the Hubble Space Telescope (HST). From a previous HST UV image (λ~2180 Å), Mrk 477 has been known to have a pointlike bright UV hot spot in the central region, peculiar among nearby Seyfert 2 galaxies. There are also claims of…
Infrared Space Observatory Observations of Hickson Compact Group 31 with the Central Wolf-Rayet Galaxy NGC 1741
Hanlon, L.; McBreen, B.; Metcalfe, L. +5 more
Hickson Compact Group (HCG) 31, consisting of the Wolf-Rayet galaxy NGC 1741 and its irregular dwarf companions, was observed using the Infrared Space Observatory. The deconvolved ISOCAM maps of the galaxies using the 7.7 and 14.3 µm (LW6 and LW3) filters are presented, along with ISOPHOT spectrometry of the central starburst region of NGC 1…
Origin of the May 1998 suprathermal particles: Solar and Heliospheric Observatory/Charge, Element, and Isotope Analysis System/(Highly) Suprathermal Time of Flight results
Wurz, P.; Klecker, B.; Wimmer-Schweingruber, R. F. +4 more
The Solar and Heliospheric Observatory/Charge, Element, and Isotope Analysis System/(Highly) Suprathermal Time of Flight ((H)STOF) mass spectrometer measures the elemental composition and the charge state distribution of ions with suprathermal energies in the range 10-4000 keV amu-1 from above the solar wind particle distribution up to …
First X-ray observations of the polar CE Gru
Cropper, Mark; Ramsay, Gavin
We report the detection of the polar CE Gru in X-rays for the first time. We find evidence for a dip seen in the hard X-ray light curve which we attribute to the accretion stream obscuring the accretion region in the lower hemisphere of the white dwarf. The X-ray spectrum can be fitted using only a shock model: there is no distinct soft X-ray comp…
The EIT coil-like structure in the March 20, 2000 eruptive prominence
Karlický, M.; Šimberová, S.
The evolution of the March 20, 2000 prominence eruption observed in the 195 Å(EIT/SOHO), Hα , (MDI/SOHO), 1-3 GHz radio and hard X-ray (BATSE) was analyzed. A unique EIT coil-like structure with a hot core, indicating an electric current, was observed at the beginning of the prominence eruption. This structure with about 5 turns was associated wit…
Ultraviolet Observations of Periodic Annular Intensity Fluctuations Propagating around Sunspots
Muglach, K.; Georgakilas, A. A.; Christopoulou, E. B.
We analyze UV observations of an isolated sunspot taken with the Transition Region and Coronal Explorer. We produced ``space/time slice images,'' which reveal periodic, inward-propagating, intensity fluctuations in the inner photospheric penumbra and periodic, outward-propagating, annular intensity fluctuations in the outer penumbra and the area a…
Chemically distinct nuclei and circumnuclear rings in lenticular galaxies NGC 4429 and NGC 7013
Sil'chenko, O. K.; Afanasiev, V. L.
The central regions of the regular lenticular galaxies NGC 4429 and NGC 7013 have been studied with the Multi-Pupil Field (Fiber) Spectrograph (MPFS) of the 6 m telescope of the Special Astrophysical Observatory RAS (Nizhnij Arkhyz, Russia) in two spectral ranges, the blue one including the strong absorption lines Mg I and Fe I and the red one inc…
Astrometry of the stellar image of U Her amplified by the circumstellar 22 GHz water masers
Vlemmings, W. H. T.; van Langevelde, H. J.; Diamond, P. J.
The 22 GHz H2O masers in the circumstellar envelope of the Mira variable star U Her have been observed with MERLIN using a phase referencing technique to determine accurate astrometric positions. The positions were compared with the optical positions obtained with the Hipparcos satellite to an accuracy of 18 mas. The absolute radio posi…
The Rate of Visual Binaries among the Brightest X-Ray Stars
Makarov, Valeri V.
Using the Tycho Double Star Catalogue and the Hipparcos Catalogue, I compare the rates of occurrence of resolved visual doubles among the brightest X-ray stars from the ROSAT All-Sky Survey Bright Source Catalog (RASS-BSC) and generally in these two catalogs. A strong correlation between visual binarity and brightness in X-rays is found. The rate …