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Australia Telescope Compact Array Observations of the OH Star Roberts 22: Resolved Images of Hydroxyl Emission
Goss, W. M.; Dyer, K. K.; Kemball, A. J.
We have imaged the unusual OH/IR object G284-0.8 (Roberts 22) in the OH transitions at 1612, 1665, and 1667 MHz using the Australia Telescope Compact Array in Narrabri, NSW, Australia. The angular resolution of the OH images we present here is 6" (12,000 AU at a distance of 2 kpc). We find OH emission of extent 1.5" (2800 AU) located inside the op…
The Confusion Limit on Astrometry with the Space Interferometry Mission
Böker, Torsten; Allen, Ronald J.; Rajagopal, Jayadev
An important requirement for the Space Interferometry Mission (SIM) is to carry out precision astrometry in crowded fields. This capability is crucial, for example, to accurately measure proper motions of bright stars in nearby galaxies. From such measurements, one can obtain distance estimates, explore the dynamics of these systems, and measure t…
The Mid-Infrared View of Star Formation in Collisional Ring Galaxies
Cesarsky, C.; Sauvage, M.; Vigroux, L. +4 more
We present mid-infrared images and spectra of Arp 10 and Arp 118, two collisional ring galaxies observed as part of the ISOCAM GT program CAMACTIV (P.I.: I.F. Mirabel). The observations reveal the distribution of hot dust in the galaxies and enable us to probe the mechanisms responsible for the heating of the ISM. Unlike the peculiar mid-infrared …
The Carlsberg Meridian Telescope: an astrometric robotic telescope
Evans, D. W.
An overview is given of the Carlsberg Meridian Telescope on La Palma, which is one of the oldest robotic telescopes, having started observing on La Palma in 1984. In the spring of 1997, a further stage of automation was made when we converted the telescope to remote operation. Since then, the telescope has been operated over the Internet from Brit…
Simultaneous Observations of Variability at All Atmospheric Levels of V824 Arae (HD 155555)
Neff, James E.; Lim, Jeremy; Dempsey, Robert C.
We conducted a multiwavelength campaign observing V824 Ara (HD 155555, G5 IV+K0 IV-V) continuously throughout one complete orbital cycle (~1.7 days) in early May of 1996. At the core of this campaign were observations using the GHRS on the Hubble Space Telescope (HST). In all, about 48,000 spectra, many in rapid readout mode, were obtained with th…
The 3-D Heliosphere at Solar Maximum
Marsden, Richard G.
Conference was held in Noordwijk, Netherlands, in 2000 October. Proceedings will be edited by R. G. Marsden and published in Space Science Reviews.
Harmonizing the RR Lyrae and clump distance scales - stretching the short distance scale to intermediate ranges?
Popowski, Piotr
I explore the consequences of making the RR Lyrae and clump giant distance scales consistent in the solar neighbourhood, Galactic bulge and Large Magellanic Cloud (LMC). I employ two major assumptions: (i) that the absolute magnitude-metallicity, MV(RR)-[Fe/H], relation for RR Lyrae stars is universal, and (ii) that absolute I magnitude…
Coherence of charged particle oscillations in the heliosphere (f~5µHz): Implications for a solar modulation source
Kunow, H.; Lanzerotti, L. J.; Gold, R. E. +3 more
Time series analysis of low-energy electron and high-energy proton cosmic ray fluxes, both measured on the Ulysses spacecraft, shows that they are quite coherent in some frequency bands in the energy range 0-6 µHz, especially near 5 µHz. Interplanetary particle fluxes with very different kinematic properties (e.g., gyrofrequencies) are…
Detection of arcs in Saturn's F ring during the 1995 Sun ring-plane crossing
Charnoz, S.; Brahic, A.; Ferrari, C. +3 more
Observations of the November 1995 Sun crossing of the Saturn's ring-plane made with the 3.6 m CFH telescope, using the UHAO adaptive optics system, are presented here. We report the detection of four arcs located in the vicinity of the F ring. They can be seen one day later in HST images. The combination of both data sets gives accurate determinat…
Decay of Magnetic Field Irregularities Observed by Ulysses
Balogh, André; Erdos, Géza; Kóta, József
We study the solar cycle, radial, and latitudinal dependence of the characteristics of magnetic field irregularities in the Heliosphere. The frequency of magnetic field discontinuities is determined, using high time resolution magnetic field observations by Ulysses, covering the time interval from 1992 to 2000. The quasi-linear scattering mean fre…