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The complex structure of the Mg II regions of 40 BeV stars
Danezis, E.; Lyratzi, E.; Theodossiou, E. +4 more
In this paper we present a study of the UV Mg II resonance lines in 40 BeV stars' spectra. We used the model proposed by Danezis et al. (2002, 2003). This model is based on the idea of independent density layers in the regions where the spectral lines that present SACs (DACs) are created. We calculated the apparent rotation (Vrot) and e…
INTEGRAL surveys
Walter, R.; Kretschmar, P.; Paizis, A. +2 more
The XMM large-scale structure survey: scientific motivation and first cluster candidates
Valtchanov, I.; Pierre, M.
The XMM-Newton Large-Scale Structure Survey (XMM-LSS) will ultimately cover a region of 8x8 square degrees and with the unprecedented sensitivity of XMM will provide a unique dataset to study the evolution of the cosmic network as traced by clusters and AGNs/QSOs. We discuss the scientific goals and show some first observations of candidate cluste…
Variability of the He I λ5876 Å line in early type chemically peculiar stars. II
Leone, F.; Catanzaro, G.
To try to understand the behavior of helium variability in Chemically Peculiar stars, we continued our on-going observational campaign started by \cite{catanzaro99}. In this paper we present a new set of time resolved spectroscopic observations of the He I 5876 Å line for a sample of 10 stars in the spectral range B3 - A2 and characterized by diff…
Energetic Particle Observations by the Cassini Spacecraft during Its Heliospheric Cruise to Saturn
Livi, S.; Dougherty, M. K.; Lario, D. +3 more
We present energetic particle observations performed by the Cassini spacecraft during its heliospheric cruise to Saturn. We cover three years of data (20002002) during the maximum of the solar cycle 23. Cassini's helio centric radial distance ranged from 2.5 to 8.0 AU. Energetic particle intensity enhancements at these distances are associated wit…
A magnetohydrodynamic simulation of the single-fluid 2-D structure of the solar wind
Xue, Jin-Tao; Wang, Jing-Fang; Qian, Xin +1 more
The system of single-fluid 2-D magnetohydrodynamic (MHD) equations incorporating the momentum term is simulated and the structure of the solar wind in the meridian plane is acquired. The form and location of the momentum addition have an important effect on the velocity and proton density of the solar wind in distant places. By locating the additi…
On the Rapid Variations of Solar Magnetic Fields
Venkatakrishnan, P.; Kumar, Brajesh; Ravindra, B.
We report on the rapid variations of solar magnetic fields that appear to be enhanced significantly above the background variability, at a few locations within the solar active regions, as observed with the Michelson Doppler Imager (MDI) on board the SOHO spacecraft. The pressure fluctuations estimated to arise from this variability far exceed the…
Acceleration Effects in MDI Magnetogram Data
Norton, A.; Settele, A.
Acceleration effects are found in the Michelson Doppler Imager (MDI) magnetogram data because changes in the line profiles during the 30-s measurement are introduced by underlying p-mode velocity variations. This imparts an oscillatory component to the magnetic flux signal. Simulated profiles using Maltby M and Harvard Smithsonian Reference Atmosp…
The Local Stellar Velocity Distribution of the Galaxy
Şuran, Marian Doru; Ionescu, Adina; Popescu, Nedelia Antonia
This paper deals with systematic [r, B-V, MV] calculations of the kinematical parameters in the solar neighbourhood using a combination of the Hipparcos and Barbier-Brossat catalogues. A series of new kinematical and dynamical features are pointed, together with severe limitations and biasing of the two catalogues. The implications for …
Compiled catalogue of MK spectral classifications, including astrometric and photometric data
Rybka, S. P.
The catalogue constructed as a tool for stellar kinematic analysis is described. It contains up-to-date information on spectral classifications in the MK system, positions and proper motions in the ICRS system, as well as BV magnitudes for 71334 single stars. Astrometry and photometry were mainly selected from the Tycho-2. MK spectral types and lu…