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Radio and X-Ray Signatures of Magnetic Reconnection behind an Ejected Flux Rope
Pick, M.; Krucker, S.; Démoulin, P. +2 more
We present a detailed study of a complex solar event observed on 2002 June 2. Joint imaging EUV, X-ray, and multiwavelength radio observations allow us to trace the development of the magnetic structure involved in this solar event up to a radial distance of the order of 2 Rsolar. The event involves type II, III, and IV bursts. The type…
Statistical Properties Of Sunspots In 1996 2004: I. Detection, North South Asymmetry And Area Distribution
Zharkova, V. V.; Zharkov, S.; Ipson, S. S.
The first statistical results in sunspot distributions in 1996-2004 obtained from the Solar Feature Catalogues (SFC) are presented. A novel robust technique is developed for automated identification of sunspots on SOHO/MDI white-light (WL) full-disk solar images. The technique applies image standardization procedures for elimination of the limb da…
Systematic uncertainties in the analysis of star cluster parameters based on broad-band imaging observations
Bastian, N.; de Grijs, R.; Anders, P. +5 more
High-resolution Hubble Space Telescope (HST) imaging observations of star cluster systems provide a very interesting and useful alternative to spectroscopic studies for stellar population analyses with 8-m class telescopes. Here, we assess the systematic uncertainties in (young) cluster age, mass and (to a lesser extent) extinction and metallicity…
Limits from the Hubble Space Telescope on a Point Source in SN 1987A
Filippenko, Alexei V.; Garnavich, Peter; Fransson, Claes +16 more
We observed supernova 1987A (SN 1987A) with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST) in 1999 September and again with the Advanced Camera for Surveys (ACS) on the HST in 2003 November. Our spectral observations cover ultraviolet (UV) and optical wavelengths from 1140 to 10266 Å, and our imaging observatio…
First results of low frequency electromagnetic wave detector of TC-2/Double Star program
Zhou, L.; Santolík, O.; Parrot, M. +17 more
LFEW is a low frequency electromagnetic wave detector mounted on TC-2, which can measure the magnetic fluctuation of low frequency electromagnetic waves. The frequency range is 8 Hz to 10 kHz. LFEW comprises a boom-mounted, three-axis search coil magnetometer, a preamplifier and an electronics box that houses a Digital Spectrum Analyzer. LFEW was …
Cassini observations of the thermal plasma in the vicinity of Saturn's main rings and the F and G rings
Gurnett, D. A.; Coates, A. J.; Thomsen, M. F. +10 more
The ion mass spectrometer on Cassini detected enhanced ion flux near Saturn's main rings that is consistent with the presence of atomic and molecular oxygen ions in the thermal plasma. The ring ``atmosphere'' and ``ionosphere'' are likely produced by UV photosputtering of the icy rings and subsequent photoionization of O2. The identific…
Three-dimensional Structure of Coronal Mass Ejections from LASCO Polarization Measurements
Wang, Dennis; Dere, Kenneth P.; Howard, Russell
The three-dimensional structure of a coronal mass ejection (CME) is essential information for understanding the process by which they are ejected from the Sun. Coronagraphic measurements readily provide information on the structure of CMEs in the plane of the sky. It has been known for some time that polarization measurements can provide informati…
Hubble Space Telescope ACS Images of the GG Tauri Circumbinary Disk
Stapelfeldt, K. R.; Ford, H. C.; Illingworth, G. D. +6 more
Hubble Space Telescope Advanced Camera for Surveys images of the young binary GG Tauri and its circumbinary disk in V and I bandpasses were obtained in 2002 and are the most detailed of this system to date. They confirm features previously seen in the disk including a ``gap'' apparently caused by shadowing from circumstellar material, an asymmetri…
The Dwarf Spheroidal Companions to M31: Variable Stars in Andromeda I and Andromeda III
Da Costa, G. S.; Pritzl, Barton J.; Armandroff, Taft E. +1 more
We present the results of variable star searches of the M31 dwarf spheroidal (dSph) companions Andromeda I and Andromeda III using the Hubble Space Telescope. A total of 100 variable stars were found in And I, while 56 were found in And III. One variable found in And I and another in And III may be type II Cepheids. In addition to this variable in…
What a local sample of spectroscopic binaries can tell us about the field binary population
Schröder, Klaus-Peter; Fisher, James; Smith, Robert Connon
We study a sample of spectroscopic binaries (SBs) in the local solar neighbourhood (d<= 100 pc and MV<= 4) in an attempt to find the distributions of the period, P, the primary mass, m1, and the mass ratio q(=m2/m1), as well as the initial mass function (IMF) of the local population of field binari…