Search Publications
X-type interactions of the loops in the flare of 25 September 1997 - Part II
Mandrini, C. H.; Siarkowski, M.; Falewicz, R. +1 more
The interaction of magnetic structures and the conversion of magnetic free energy into heating of the plasma and acceleration of particles are commonly accepted as the origin of solar flares. The 3-dimensional (3D) structure and evolution of the coronal magnetic field can be investigated indirectly by the analysis of the images of various loops fi…
The Accretion Disk and White Dwarf during the Quiescence of the Dwarf Novae VW Vulpeculae and χ Leonis
Sion, Edward M.; Henry, Colleen K.
We have carried out an International Ultraviolet Explorer archival comparative study of the two U Geminorum type dwarf novae VW Vulpeculae and χ Leonis. The spectrum of χ Leo does not show any C IV, a feature normally seen in the vast majority of other dwarf novae. For VW Vul, a single-temperature high-gravity photosphere does not produce a consis…
A search for the optical counterpart to PSR B1821-24 in M 28
Golden, A.; Shearer, A.; Butler, R. F.
We have analysed archival HST/WFPC2 images in both the F555W & F814W bands of the core field of the globular cluster M 28 in an attempt to identify the optical counterpart of the magnetospherically active millisecond pulsar PSR B1821-24. Examination of the radio derived error circle yielded several potential candidates, down to a magnitude of …
ULF wave observations in Jupiter's magnetosphere
Dougherty, Michele K.; Petkaki, Panagiota
In previous work we have examined magnetometer data from the Ulysses Jupiter flyby, and in particular middle magnetosphere observations in the vicinity of the magnetodisk. Waves transverse to the background magnetic field were found in the heavy ion gyrofrequency regime, a signature of Ion Cyclotron (IC) waves. We examined the dayside and high lat…
The Fall 2000 and Fall 2001 SOHO-Ulysses Quadratures
Suess, S.; Poletto, G.
SOHO-Ulysses quadrature occurs when their included angle with the Sun is 90°. At these times the same plasma leaving the Sun in the direction of Ulysses can first be remotely analyzed with SOHO and then later be sampled in situ at Ulysses. Quadratures in Fall 2000/2001 are of special interest because Ulysses will be near the south and north heliog…
Observation of long-duration gyroharmonic resonances: A refutation of the short-duration explanation for interpreting the anomalous URAP sounder spectra observed in the Io torus
Canu, Patrick
The resonance spectra collected by the Ulysses Unified Radio and Plasma Wave relaxation sounder in the Jovian magnetosphere at the outskirts of the Io torus exhibit significant differences from those gathered from earthbound spacecraft. The main deviation is the lack of resonances at the harmonics of the electron gyrofrequency. Extrapolated from s…
Distances of Globular Clusters based on Hipparcos Parallaxes of Nearby Subdwarfs
Lee, Sang-Gak; Saad, Somaya Mohamed
In the present study we have determined the distance moduli for seven globular clusters M2, M3, M10, M12, NGC 2808, NGC 6229 and NGC 6752, whose metallicities are in the range -1.54 < [Fe/H] < -1.10. We have derived distances for them by the main-sequence fitting method using a sample of local subdwarfs, whose accurate parallaxes are taken f…
Hipparcos Proper-Motion System with Respect to SPM 2.0
Zhu, Zi
On the basis of Hipparcos data, whose system is believed to be quasi-inertial to within +/-0.25 mas yr-1 and to represent an internally consistent reference frame, we carried out an analysis of the SPM 2.0 proper-motion system. Comparing the Hipparcos proper motions with those of the SPM 2.0 Catalog, which provides absolute proper motio…
HST/FOC Imaging of Triton
Stern, S. A.; Stansberry, J.; Flynn, B. +1 more
We present an analysis of HST/FOC images of Triton obtained on 20-24 September 1995. Images were taken in two wavelength bands using the F278M and F410M filters in order to obtain the first mid-UV map of Triton and to place further compositional constraints on Triton's surface by imaging farther into the UV than did Voyager. Our disk-resolved imag…
Deep imaging of Q2112+059: A bright host galaxy but no DLA absorber
Møller, P.; Thomsen, B.; Fynbo, J. U.
In an ongoing programme aimed at studying galaxy counterparts of Damped Lyα Absorbers (DLAs) we have obtained high resolution deep I-band imaging data of the field around the zem = 0.457 BAL QSO Q2112+059. In the literature this QSO is listed to have a candidate DLA at zabs = 0.2039 along the line of sight. After subtraction …