Search Publications

A flux enhancement measured in energetic particles(E ∼ 60-100 keV) by the epona instrument aboard Giotto close to P⧸Grigg-Skjellerup, and its interpretationas the signature of a companion comet

McKenna-Lawlor, Susan M. P.; Afonin, Valerie V.

A significant flux enhancement in energetic particles (E ∼ 60-⩾260 keV),showing internal fine structure interpreted to represent signatures produced during the traversalof various cometary boundaries in P⧸Grigg-Skjellerup, was recorded by the EPONA instrumentaboard spacecraft Giotto on 10 July 1992. A further internally structured flux enhancement…

Ultra-Luminous IR Galaxies at Low and High Redshift

Scoville, Nick

In the luminous infrared galaxies, nuclear starbursts and active nuclei are fueled by extraordinarily large masses of gas and dust concentrated at radii of a few hundred pc by galactic merging and viscous accretion. The nearby ULIRGS are probably excellent analogs of galaxies seen at high redshift during the epoch of galaxy formation and growth. W…

Comparison of Polar and Equatorial Coronal Holes Observed by UVCS/SOHO: Geometry and Physical Properties

Dobrzycka, D.; Kohl, J.; Strachan, L. +1 more

We analyzed UVCS/SOHO data and compared the H I Lyα (121.6 nm) and O VI (103.2 nm, 103.7 nm) emission in the polar and equatorial coronal holes. We found that the emission lines have similar characteristics in these two types of coronal holes. Both types show evidence for superradially diverging boundaries. The latitudinal distribution of the O VI…

Chemically decoupled nucleus and the structure of the nuclear region in the spiral galaxy NGC 488

Sil'chenko, O. K.

The regular Sb-type galaxy NGC 488 was observed at the 6-meter telescope with the Multi-Pupil Field Spectrograph and found to have a chemically decoupled nucleus. Stellar population in the nucleus is twice richer in metals than that of the central bulge. An analysis of the isophotal shapes in the central part of the galaxy based on the images obta…

Charge sign dependent modulation: Ulysses COSPIN/KET results

Sierks, H.; Kunow, H.; Bothmer, V. +8 more

According to drift dominated modulation models galactic cosmic ray protons and electrons respond differently to the latitudinal extension of the heliospheric current sheet. In an A 0 solar magnetic cycle intensities of ¥ positively charged particles should vary only weakly with the latitudinal extension, whereas electrons should show a much strong…

Effects of anisotropic perpendicular diffusion on the energy and spatial dependence of galactic electron modulation in the heliosphere

Potgieter, M. S.; Ferreira, Stefan

Perpendicular diffusion enhanced in the polar directions of the heliosphere seems required in numerical models based on Parker's transport equation for cosmic rays, especially in explaining the small latitudinal gradients observed for protons by the Ulysses spacecraft during its fast latitude scan. This modulation topic is further studied using el…

Hubble Space Telescope Observations of Planets and Satellites

James, Philip B.; Lee, Steven W.

Although exploration by remote, in situ spacecraft has been the primary tool used in scientific exploration of the planets and other solar system objects for the last three decades, the unique capabilities of the Hubble Space Telescope (HST) have made it an invaluable tool for solar system research and have led to many important discoveries. HST's…

Hubble Space Telescope WFPC2 Color-Magnitude Diagram of NGC 6287

Stetson, P. B.; Kellar Fullton, L.; Carney, B. W.

An Estimation of the Galactic Escape Velocity From High-Velocity Metal-Poor Stars

Meillon, L.

A large number of high-velocity stars was included in the Hipparcos Input Catalogue for the purpose of determining the galactic escape velocity in the solar vicinity. However, the `fastest' stars known, listed by Carney et al. (1994, CLLA) were not included because they are too faint. In the intersection between the CLLA list and the Hipparcos Cat…

Radio star catalogue observed in San Juan (RSSJ95)

Manrique, W. T.; Perdomo, R.; Podesta, R. C. +2 more

Using the data observed in San Juan with the photoelectric Astrolabe Mark II of the Beijing Astronomical Observatory from February, 1992 to March, 1997, the radio star catalogue in San Juan(RSSJ95) has been compiled. There are 69 radio stars in this catalogue. The positions of the radio stars are for the epoch of observation and the equinox J2000.…