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Discovery of a 3.6 hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214
Tennant, Allyn F.; Swartz, Douglas A.; Ghosh, Kajal K. +3 more
We report the discovery of an eclipsing X-ray binary with a 3.62 hr period within 24" of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an…
Multiple triangulation analysis: application to determine the velocity of 2-D structures
Zong, Q. -G.; Cao, J. B.; Shi, Q. Q. +4 more
In order to avoid the ambiguity of the application of the Triangulation Method (multi-spacecraft timing method) to two-dimensional structures, another version of this method, the Multiple Triangulation Analysis (MTA) is used, to calculate the velocities of these structures based on 4-point measurements. We describe the principle of MTA and apply t…
MK Classification and Dynamical Masses for Late-Type Visual Binaries
Docobo, José A.; Tamazian, Vakhtang S.; Melikian, Norair D. +1 more
On the basis of slit spectra obtained with the SCORPIO spectral camera attached to the 2.6 m telescope of the V. Ambartsumian Byurakan Astrophysical Observatory (Armenia), MK classifications for 30 visual binaries comprising mostly late K and M type stars are presented. Comparison with other determinations shows that this configuration provides a …
The Einstein Ring 0047-2808 Revisited: A Bayesian Inversion
Brewer, B. J.; Lewis, G. F.
In a previous paper, we outlined a new Bayesian method for inferring the properties of extended gravitational lenses given data in the form of resolved images. This method holds the most promise for optimally extracting information from the observed image, while providing reliable uncertainties in all parameters. Here, we apply the method to the w…
Periodicities in Irradiance and in other Solar Activity Indices During Cycle 23
Özgüç, A.; Ataç, T.; Rybak, J.
Magnetic fields give rise to distinctive features in different solar atmospheric regimes. To study this, time variations of the flare index, sunspot number and sunspot area, each index arising from different physical conditions, were compared with the solar composite irradiance throughout cycle 23. Rieger-type periodicities in these time series we…
Statistical study of the location and size of the electron edge of the Low-Latitude Boundary Layer as observed by Cluster at mid-altitudes
Fazakerley, A. N.; Klecker, B.; Owen, C. J. +2 more
The nature of particle precipitations at dayside mid-altitudes can be interpreted in terms of the evolution of reconnected field lines. Due to the difference between electron and ion parallel velocities, two distinct boundary layers should be observed at mid-altitudes between the boundary between open and closed field lines and the injections in t…
Doppler Shift Correlations in the Solar Transition Region
Doschek, G. A.
I investigate dynamical correlations between the lower transition region and the upper transition region using spectra from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) spacecraft. The measured quantity is the Doppler shift (mostly solar radial) along the line of sigh…
Irradiated atmospheres of accreting magnetic white dwarfs with an application to the polar AM Herculis
Gänsicke, B. T.; Beuermann, K.; König, M.
We present a pilot study of atmospheres of accreting magnetic white dwarfs irradiated by intense fluxes at ultraviolet to infrared wavelengths. The model uses a standard LTE stellar atmosphere code which is expanded by introducing an angle-dependent external radiation source. The present results are obtained for an external source with the spectra…
Outstanding aeronomy problems at Venus
Witasse, O.; Nagy, A. F.
Of all the non-terrestrial ionospheres and thermospheres in our solar system those of Venus have been explored and studied the most. This is mainly because of the 14 year exploration of the well-instrumented Pioneer Venus spacecraft and the theoretical studies prompted by the resulting observational information. However, there are still a number o…
Characterizing three candidate magnetic cataclysmic variables from SDSS: XMM-Newton and optical follow-up observations.
Szkody, P.; Henden, A.; Schmidt, G. D. +4 more
In the latest in our series of papers on XMM-Newton and ground-based optical follow-up of new candidate magnetic cataclysmic variables (mCVs) found in the Sloan Digital Sky Survey, we report classifications of three systems: SDSS J144659.95+025330.3, SDSS J205017.84-053626.8, and SDSS J210131.26+105251.5. Both the X-ray and optical fluxes of SDSS …