Search Publications
Impact of the Ulysses velocity on the diagnosis of the electron density by the Unified Radio and Plasma Wave sounder in the outskirts of the Io torus
Canu, Patrick; Cornilleau-Wehrlin, Nicole; Le Sager, Philippe
The resonance spectra collected on February 8, 1992, in the outskirts of the Io plasma torus by the Unified Radio and Plasma wave (URAP) relaxation sounder on board the Ulysses spacecraft present significant differences from the active spectra gathered by earthbound spacecraft in similar plasma conditions. The most striking anomaly is the lack of …
Kinematic evidence for the wave nature of the Carina-Sagittarius arm
Dambis, A. K.; Rastorguev, A. S.; Sitnik, T. G. +2 more
Radial-velocity and (Hipparcos) proper-motion data are used to construct the residual space velocity field for OB associations in the Carina-Sagittarius arm. The azimuthal residual velocity component for most stars in the Sgr OB1, Ser OB1, Cru OB1, Cen OB1, and Car OB2 associations has the direction that is opposite to the Galactic rotation, while…
Decomposition of the rotation curves of distant field galaxies
Möllenhoff, C.; Fuchs, B.; Heidt, H.
We present decompositions of the rotation curves of distant spiral galaxies into contributions due to their bulges, disks, and putative dark haloes. In order to set constraints on the ambiguities of the decompositons we interpret the morphology of the spiral structures quantitatively in the framework of density wave theory. Galaxy models constrain…
ISO-SWS Observations of Weak Bands of Trace Components of Ices Towards the Young Stellar Object W 33A
van Dishoeck, E. F.; Whittet, D. C. B.; Schutte, W. A. +3 more
ISO-SWS observations of the highly obscured young stellar object W 33A reveal two broad absorption features centered at 7.24 and 7.40 µm. The position and width of these features indicates that they are due to the XH bending mode (X = C, N, or O) of molecules in the solid state. Comparison to interstellar ice analogs shows that the 7.24 µm band ca…
Surface Photometry of the Dwarf Elliptical Galaxies NGC 185 and NGC 205
Lee, Myung Gyoon; Kim, Sang Chul
We present BVRI CCD surface photometry for the central (6'.35 X 6'.35) regions of the dwarf elliptical galaxies NGC 185 and NGC 205 in the Local Group. Surface brightness profiles of NGC 185 (R < 225") and NGC 205 (R < 186") show excess components in the central regions. The colors of NGC 185 get bluer inward at R < 25", while they remain…
Spatially Resolved Spectra of 3C Galaxy Nuclei
Nelson, C.; Hutchings, J. B.; Kaiser, M. E. +3 more
We present and discuss visible-wavelength long-slit spectra of four low-redshift 3C galaxies obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST). The slit was aligned with near-nuclear jetlike structure seen in HST images of the galaxies, to give unprecedented spatial resolution of their inner regions. In 3C …
Kinematic Substructure of Halo Stars from HIPPARCOS Observations
Chen, B.
With highly accurate parallaxes and proper motions observed by HIPPARCOS, we discuss the distributions of velocities and metallicities for a sample of stars selected from the Lowell Proper Motion Catalog. Cluster analysis is used to search for natural groups in the sample and display them graphically. Data presented in this Letter support the pict…
The Cassini Ion Mass Spectrometer: Performance Metrics and Techniques
McComas, D. J.; Young, D. T.; Goldstein, R. +7 more
The Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS) uses a unique electric field configuration coupled with precise sub-nanosecond timing to produce a high mass-resolution plasma analyzer with both broad energy and mass ranges. The IMS maintains a spectrographic mass resolution (m/Δm) of ≥50 over a mass range of 1 to 40amu for singl…
Synoptic measurements of Martian winds using the Hubble Space Telescope
Crisp, David; Bell, James F., III; Mischna, Michael A. +1 more
We used the Hubble Space Telescope to make wind speed and wind direction measurements of the Martian atmosphere during early northern summer (Ls=97°). Our strategy utilized a series of near-UV images with optimal temporal sampling to track observable cloud features and to determine the direction and speed of cloud motion. Several techni…
Ulysses and WIND particle observations of the November 1997 solar events
Lario, D.; Balogh, A.; Maksimovic, M. +5 more
The episode of intense solar activity on 4 and 6 November 1997 resulted in large and extended particle events observed by the Ulysses and WIND spacecraft. Ulysses was at a heliocentric distance of 5.34 AU, very close to the solar equator and 100° west in heliolongitude from earth. WIND was near the earth at 0.99 AU from the Sun and in the ecliptic…