Search Publications
OB stars in the Tycho-2 and 2MASS catalogues
Gontcharov, G. A.
The Tycho-2 proper motions and five-band Tycho-2 and 2MASS photometry for approximately 2.5 million common stars have been used to select OB stars and to determine the extinction and photometric distance for each of them. We have selected 37 485 stars and calculated their reddenings based on their positions in the two-color V T - H, J-…
Cluster observations on the thin current sheet in the magnetotail
Dandouras, I.; Rème, H.; Cao, J. B. +3 more
A magnetotail event on 15 September 2001 is analyzed, during which the Cluster spacecraft observed both embedding and bifurcation of the Thin Current Sheet (TCS). It is indicated that the ion anisotropy and nongyrotropy are responsible for those new equilibrium features that represent deviations from the conventional Harris model. Measurements sho…
Multi-Spacecraft Methods of Wave Field Characterisation
Glassmeier, Karl-Heinz; Pinçon, Jean-Louis
Space plasmas are collisionless and thus waves play a major role in the collective interaction between particles. Also, space plasmas are subject to a variety of instabilities, generating a plethora of different plasma wave modes. Thus, for many physical processes the role of waves and turbulence is likely to be predominant. The simultaneous four-…
SUMER-Hinode observations of microflares: excitation of molecular hydrogen
Innes, D. E.
Context: Concentrations of H2 have been detected by SUMER in active region plage. The H2 is excited by O VI line emission at 1031.94 Å which, although not observed, must be brightening along with the observed transition region line, Si III 1113.24 Å.
Aims: We investigate the excitation of H2 and demonstrate the association between the observed…
The FERRUM project: experimental and theoretical transition rates of forbidden [Sc II] lines and radiative lifetimes of metastable Sc II levels
Lundberg, H.; Hartman, H.; Hibbert, A. +6 more
Context: In many plasmas, long-lived metastable atomic levels are depopulated by collisions (quenched) before they decay radiatively. In low-density regions, however, the low collision rate may allow depopulation by electric dipole (E1) forbidden radiative transitions, so-called forbidden lines (mainly M1 and E2 transitions). If the atomic transit…
Implication for Super-Critical Accretion Flow in the Narrow-Line Seyfert 1 Galaxy PKS 0558-504
Kunieda, Hideyo; Haba, Yoshito; Terashima, Yuichi +1 more
We present results from XMM-Newton observations of the narrow-line Seyfert 1 galaxy PKS0558-504. The 2-12keV X-ray spectra can be well-reproduced by a single power law with a photon index of ∼2.2. The extrapolation of this power law continuum into the lower energy band reveals the existence of a strong soft excess component. When we applied a mult…
Evaluation of bispectrum in the wave number domain based on multi-point measurements
Glassmeier, K. -H.; Décréau, P. M. E.; Narita, Y. +3 more
We present an estimator of the bispectrum, a measure of three-wave couplings. It is evaluated directly in the wave number domain using a limited number of detectors. The ability of the bispectrum estimator is examined numerically and then it is applied to fluctuations of magnetic field and electron density in the terrestrial foreshock region obser…
Statistical study of radio drifting pulsation structures with associated CMEs and other observations
Yan, Y. H.; Liu, Y. Y.; Wang, S. J. +5 more
Solar radio burst, especially the fine structures (FSs) and the drifting pulsation structures (DPSs), may be used as an important diagnostics tool to draw the evolution map of the flare loop in the initial phase of solar flares. In this work, 52 radio events were found accompanying with DPSs. They were all observed with the Solar Radio Spectromete…
Spitzer mid-infrared study of compact H II regions in the Magellanic Clouds
Heydari-Malayeri, M.; Charmandaris, V.; Chatzopoulos, E.
Aims: We present a study of the mid-infrared properties and dust content of a sample of 27 H ii “blobs”, a rare class of compact H ii regions in the Magellanic Clouds. A unique feature of this sample is that even though these H ii regions are of high and low excitation they have nearly the same physical sizes ~1.5-3 pc.
Methods: We base our an…
Modeling Pulsar Wind Nebulae
Bucciantini, N.
In the last few years, new observations by CHANDRA and XMM have shown that Pulsar Wind Nebulae present complex but similar inner features, with the presence of axisymmetric rings and jets, which are generally referred to as a jet-torus structure. Due to the rapid growth in accuracy and robustness of numerical schemes for relativistic fluid-dynamic…