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Ground-based and satellite observations of high-latitude auroral activity in the dusk sector of the auroral oval
Janhunen, P.; Orsini, S.; André, M. +18 more
On 7 December 2000, during 13:30-15:30 UT the MIRACLE all-sky camera at Ny Ålesund observed auroras at high-latitudes (MLAT ~ 76) simultaneously when the Cluster spacecraft were skimming the magnetopause in the same MLT sector (at ~ 16:00-18:00 MLT). The location of the auroras (near the ionospheric convection reversal boundary) and the clear corr…
Surface Photometry of Spiral Galaxies at Redshifts 0.15 to 1
Tamm, A.; Tenjes, P.
Using HST archive observations for three disk galaxies at redshifts z = 0.15, 0.90 and 0.99, and the astronomical data processing system IRAF/STSDAS, we derived their surface brightness profiles. Derived luminosity distributions were reduced to standard V and I magnitudes. After corrections for cosmological distortion (k-correction), the surface b…
The galactic motion field of K0-5 giants from Hipparcos data
Schwan, H.; Brosche, P.; Schwarz, O.
We have investigated the motions of all K0-5 stars which have a proper motion in the Hipparcos catalogue and a known luminosity class III (due to the incompleteness of the ongoing classification, the distribution of these stars at the celestial sphere is rather uneven). We have used the apparent magnitudes and colours together with adopted means a…
Langmuir Wave Activity: Comparing the Ulysses Solar Minimum and Solar Maximum Orbits
McComas, D. J.; Lin, Naiguo; MacDowall, R. J.
We examine the occurrence and intensity of Langmuir wave activity (electrostatic waves at the electron plasma frequency) during the solar minimum and solar maximum orbits of Ulysses. At high latitudes during the solar minimum orbit, occurrences of Langmuir waves in magnetic holes were frequent; in the second orbit, they were less common. This diff…
In situ Wave Phenomena Associated with Magnetic Clouds and Other Ejecta
MacDowall, R. J.; Thejappa, G.
We present Ulysses Unified Radio and Plasma Wave (URAP) observations of ion-acoustic waves associated with magnetic clouds and ejecta. The peak intensities of these waves, which usually occur inside CMEs when T e/ T i≫1, are not correlated with heliocentric distance or electron to ion temperature ratio inside the CMEs.
On the Photometric Variability of Red Clump Giants
Adelman, Saul J.
Hipparcos photometry of the 308 red clump giants identified by Paczynski et al. (1999) is investigated. These stars are found to be quite stable during the three years of observation, but questions remain about longer term stability.
ISOCAM Observations of a Galaxy Merging Sequence
Charmandaris, V.; Mirabel, I. F.; Gallais, P. +1 more
We present mid-IR (5–16µm) images and spectra of a sequence of interacting galaxies, observed by ISOCAM. The galaxies were selected as being at progressive stages in the time evolution of a merging event and having no detected contribution from an active galactic nucleus (AGN) in their mid-IR spectrum. To trace the intensity of the global st…
The Orbit and Spectral Line Variations of the Massive Binary HD 163181 (V453 Scorpii)
Wang, Z.; Gies, D. R.; Bagnuolo, W. G., Jr. +3 more
We present revised orbital elements for the massive interacting binary HD 163181, and we offer the first evidence of apsidal motion in the orbit (apsidal period U=510+/-100 yr). We searched for but found no obvious evidence of the secondary's spectral lines in our optical spectra. We do observe, however, systematic profile variations with orbital …
The Dust Temperature of the ``Dusty'' Radio Galaxy MG 1019+0535: Evidence for an Outflow
Spinrad, Hyron; Manning, Curtis
Radio galaxies characteristically have strong Lyα emission lines. However, a few have Lyα equivalent widths that are substantially weaker in relation to other emission lines. One in particular, MG 1019+0535 (z=2.765), was studied by Dey, Spinrad, & Dickinson in 1995. We report on our reduction of Infrared Space Observatory (ISO) data in the 16…
Solar Si XI Line Ratios Observed by the Normal Incidence Spectrometer on SOHO CDS
Brooks, D. H.; Thompson, W. T.; Lang, J. +3 more
New measurements of line intensity ratios in the Be-like ion Si xi are presented for observations of the quiet Sun, active regions, coronal holes and above-limb regions obtained using the Coronal Diagnostic Spectrometer on the Solar and Heliospheric Observatory. A model ion, constructed using the best available atomic data, is used to predict the …