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Small scale structure in circumstellar envelopes and the origin of globules in planetary nebulae
Mauron, N.; Huggins, P. J.
We analyze the small scale structure in the circumstellar envelopes of NGC 7027 and IRC+10216, using high resolution optical images in dust scattered light. We use the observations to test the proposal that globules in planetary nebulae, typified by globules in the Helix nebula, originate in high density contrast proto-globules in the atmosphere o…
Hubble Space Telescope Imaging of Bipolar Nuclear Shells in the Disturbed Virgo Cluster Galaxy NGC 4438
Kenney, Jeffrey D. P.; Yale, Elizabeth E.
We present broadband and narrowband Hubble Space Telescope (HST) images of the central region of the heavily disturbed Virgo cluster galaxy NGC 4438 (Arp 120), whose nucleus has been described as a type 1 LINER or dwarf Seyfert galaxy. Narrowband Hα and [N II] HST images reveal striking bipolar shell features, 1 kpc in projected length from end to…
Production, Outflow Velocity, and Radial Distribution of H2O and OH in the Coma of Comet C/1995 O1 (Hale-Bopp) from Wide-Field Imaging of OH
Harris, Walter M.; Scherb, Frank; Mierkiewicz, Edwin +2 more
Observations of OH are a useful proxy of the water production rate (QH2O) and outflow velocity (VH2O) in comets. From wide-field images taken on 1997 March 28 and April 8 that capture the entire scale length of the OH coma of comet C/1995 O1 (Hale-Bopp), we obtain QOH from the model-independen…
Polar magnetic fields - Filaments and the zero-flux contour
Durrant, C. J.
We investigate the reliability with which magnetograph observations of the large-scale polar fields establish the zero-flux contour by comparing magnetic maps from various sources with one another and with the locations of filament structures seen on the disk in Hα filtergrams. The daily MWO and NSOKP magnetograms smoothed over 120 arc sec provide…
Kinematics of Galaxies in the Hubble Deep Field-South: Discovery of a Very Massive Spiral Galaxy at z = 0.6
Aussel, H.; Genzel, R.; Franceschini, A. +3 more
We report the first results from a study of the internal kinematics, based on spatially resolved Hα velocity profiles, of three galaxies at redshift z~0.6 and one at redshift z~0.8, detected by ISOCAM in the Hubble Deep Field-South. The kinematics are derived from high-resolution near-IR Very Large Telescope spectroscopy. One of the galaxies is a …
Restrictions to the galaxy evolutionary models from the Hawaiian Deep Fields SSA13 and SSA22
Aguerri, J. A. L.; Trujillo, I.
Quantitative structural analysis of the galaxies present in the Hawaiian Deep Fields SSA13 and SSA22 is reported. The structural parameters of the galaxies have been obtained automatically by fitting a two-component model (Sérsic r1/n bulge and exponential disc) to the surface brightness of the galaxies. The galaxies were classified on …
3-20 MeV Electrons in the Inner Three-dimensional Heliosphere at Solar Maximum: Ulysses COSPIN/KET Observations
Fichtner, H.; Schlickeiser, R.; Kunow, H. +10 more
The Ulysses trajectory provides a unique opportunity to study the propagation of MeV electrons in a wide range of heliographic latitudes and during varying conditions in the inner heliosphere. From the Ulysses launch up to the beginning of 1998, the 3-10 MeV electron count rate of the COSPIN/KET instrument has been consistently described by modula…
Old elliptical galaxies at z ~= 1.5 and the Kormendy relation
Stern, D.; McLure, R. J.; Dunlop, J. S. +8 more
Deep spectroscopy of the two Leiden-Berkeley Deep Survey mJy radio galaxies LBDS 53W069 and 53W091 has previously shown them to have old (>~3 Gyr) stellar populations at z~= 1.5. Here we present the results of Hubble Space Telescope (HST) observations with the Wide Field and Planetary Camera 2 (WFPC2) in F814W and with the Near-Infrared Camera …
Enhancement of the helium resonance lines in the solar atmosphere by suprathermal electron excitation - I. Non-thermal transport of helium ions
Jordan, C.; Smith, G. R.
Models of the solar transition region made from lines other than those of helium cannot account for the strength of the helium lines. However, the collisional excitation rates of the helium resonance lines are unusually sensitive to the energy of the exciting electrons. Non-thermal motions in the transition region could drive slowly ionizing heliu…
The composition of the solar wind
Wimmer-Schweingruber, Robert F.
Accurate knowledge of the composition of the solar wind and of solar system abundances allows us to improve our understanding about various processes affecting the elemental, isotopic, and charge-state abundances of the solar wind. During the evolution of the Sun, isotopic and elemental abundances have been affected by migration processes at the i…