Search Publications
Two new systems with enhanced UV line flux ratios as indication of the evolution of cataclysmic variables
Sanad, M. R.
We present ultraviolet spectra of 62 cataclysmic variables observed with Hubble Space Telescope Space Telescope Imaging Spectrograph & Faint Object Spectrograph (HST STIS FOS) to diagnose cataclysmic variables with enhanced NV/C IV line flux ratios. We concentrated on calculating the line flux ratios of the above mentioned sample. We found tha…
A Search for Satellites around Ceres
Russell, C. T.; Stern, S. A.; Young, E. F. +5 more
We conducted a satellite search around the dwarf planet 1 Ceres using Hubble Space Telescope and ground-based Palomar data. No candidate objects were found orbiting Ceres in its entire stability region down to ~500 km from the surface of Ceres. Assuming a satellite would have the same albedo as Ceres, which has a visual geometric albedo of 0.07-0.…
Study of nonthermal continuum patches: Wave propagation and plasmapause study
Vallières, Xavier; Grimald, S.; El-Lemdani-Mazouz, F. +3 more
Nonthermal continuum (NTC) radiation is believed to be emitted at the plasmapause and near the magnetic equator. We present a particular type of NTC radiation, referred to as NTC patch, which appears over a wide frequency range and within a relatively short time interval. NTC patches are observed in all magnetospheric plasma environments of the Cl…
`Active Longitudes' in the Heliomagnetic Reference Frame
Obridko, V. N.; Ivanov, E. V.; Chertoprud, V. E.
A new coordinate system - heliomagnetic reference frame - has been proposed in which the great circle passes through the solar pole and the north pole of the magnetic dipole is considered as the central meridian. It is shown that, in the new coordinate system, the active longitudes are defined much more clearly, are more stable in time, and are in…
Measurements of the helium 584 Å airglow during the Cassini flyby of Venus
Esposito, L. W.; Gérard, J. -C.; Hubert, B. +2 more
The helium resonance line at 584 Å has been observed with the UltraViolet Imaging Spectrograph (UVIS) Extreme Ultraviolet channel during the flyby of Venus by Cassini at a period of high solar activity. The brightness was measured along the disk from the morning terminator up to the bright limb near local noon. The mean disk intensity was ∼320 R, …
Properties of Supergranulation During the Solar Minima of Cycles 22/23 and 23/24
Williams, Peter E.; Pesnell, W. Dean
The solar minimum at the transition from cycle 23 to 24 was notable for its low level of activity and its extended duration. Among the various fields of study, the evolution of the solar convection zone may provide insight into the causes and consequences of this recent minimum. This study continues previous investigations of the characteristics o…
Multiwavelength study of Chandra X-ray sources in the Antennae
Hayward, T. L.; Brandl, B. R.; Eikenberry, S. S. +7 more
We use Wide-field InfraRed Camera (WIRC) infrared (IR) images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources to search for counterpart candidates. Using our proven frame-tie technique, we find 38 X-ray sources with IR counterparts, almost doubling the number of IR counterparts to X-ray sources that…
Evolution of large-scale magnetosonic structures to trains of solitary waves
Stasiewicz, K.; Thidé, B.; Cheng, C. Z. +1 more
Large-amplitude magnetic pulsations on ion inertial length scales are often observed in space plasmas, but their theoretical explanation is still controversial. We discuss a possible mechanism, different from ideas based on the classical plasma instabilities, for the generation of these pulsations. It is demonstrated that a competition between dis…
Observations of a high-latitude stable electron auroral emission at ∼16 MLT during a large substorm
Cattell, C.; Dombeck, J.; Preiwisch, A. +8 more
During an interval when the interplanetary magnetic field was large and primarily duskward and southward, a stable region of auroral emission was observed on 17 August 2001 by IMAGE at ∼16 magnetic local time, poleward of the main aurora, for 1 h, from before the onset of a large substorm through the recovery phase. In a region where ions showed t…
Interactions of the heliospheric current and plasma sheets with the bow shock: Cluster and Polar observations in the magnetosheath
Russell, Christopher T.; Farrugia, Charles J.; Scudder, Jack D. +7 more
On 12 March 2001, the Polar and Cluster spacecraft were at subsolar and cusp latitudes in the dayside magnetosheath, respectively, where they monitored the passage by Earth of a large-scale planar structure containing the high-density heliospheric plasma sheet (HPS) and the embedded current sheet. Over significant intervals, as the magnetic hole o…