Search Publications
Line intensity enhancements in stellar coronal X-ray spectra due to opacity effects
Mathioudakis, M.; Keenan, F. P.; Matranga, M. +2 more
Context: The I(15.01 Å)/I(16.78 Å) emission line intensity ratio in Fe xvii has been reported to deviate from its theoretical value in solar and stellar X-ray spectra. This is attributed to opacity in the 15.01 Å line, leading to a reduction in its intensity, and was interpreted in terms of a geometry in which the emitters and absorbers are spatia…
Phase-dependent X-ray observations of the β Lyrae system. No eclipse in the soft band
Hamann, W. -R.; Oskinova, L. M.; Ignace, R. +2 more
Aims:We report on observations of the eclipsing and interacting binary β Lyrae from the Suzaku X-ray telescope. This system involves an early B star embedded in an optically and geometrically thick disk that is siphoning atmospheric gases from a less massive late B II companion.
Methods: Motivated by an unpublished X-ray spectrum from the Eins…
Prominence modelling: from observed emission measures to temperature profiles
Heinzel, P.; Anzer, U.
Aims:We outline the construction of prominence - corona transition region models based upon the observations of one particular prominence.
Methods: The differential emission measure curves from observations were approximated by simple analytical functions. On this basis we constructed the temperature curve and calculated the radiative losses, …
Quiescent X-ray emission from the M9 dwarf LHS 2065
Schmitt, J. H. M. M.; Robrade, J.
Aims: X-ray emission is an important diagnostics to study magnetic activity in very low mass stars that are presumably fully convective and have an effectively neutral photosphere.
Methods: We investigate an archival XMM-Newton observation of LHS 2065, an ultracool dwarf with spectral type M9.
Results: We clearly detect LHS 2065 at soft X-…
INTEGRAL observation of the accreting pulsar 1E1145.1-6141
Santangelo, A.; Segreto, A.; Ferrigno, C. +2 more
Aims: We analyze 1050 ks of INTEGRAL data of the high mass X-ray binary pulsar 1E 1145.1-6141 to study its properties over a long time baseline, from June 2003 to June 2004, with wide spectral coverage.
Methods: We study three high luminosity episodes, two of them at the system apoastron, three brightening with lower intensity, two at the peri…
Internal kinematics of spiral galaxies in distant clusters. III. Velocity fields from FORS2/MXU spectroscopy
Böhm, A.; Peletier, R. F.; Kuntschner, H. +8 more
Context: We continue our investigation on how the cluster environment affects the evolution of galaxies.
Aims: By examining both galaxy structure and internal kinematics of cluster galaxies at lookback times of ~5 Gyr we study the nature and impact of possible interactions at the peak epoch of cluster assembly.
Methods: Going beyond our pr…
SUMER observations of the inverse Evershed effect in the transition region above a sunspot
Solanki, S. K.; Curdt, W.; Teriaca, L.
Aims: We analyse SUMER spectral scans of a large sunspot within active region NOAA 10923, obtained on 14-15 November 2006, to determine the morphology and dynamics of the sunspot atmosphere at different heights/temperatures.
Methods: The data analysed here consist of spectroheliograms in the continuum around 142.0 nm and in the Si iv 140.2 nm,…
Different triggering mechanisms for solar flares and coronal mass ejections
Lippiello, E.; de Arcangelis, L.; Godano, C.
Context: Experimental observations indicate that flares and CMEs are often associated, even if the precise relationship between the two phenomena is a still hot and open question.
Aims: We present a study of the statistical properties of solar flare and CME temporal organisation, in order to enlighten differences in the mechanisms at the basis…
Correcting for background changes in CoRoT exoplanet data
Auvergne, M.; Costa, J. E. S.; Samadi, R. +4 more
Context: The CoRoT satellite is a highly accurate photometer with 2 channels respectively optimised for asteroseismology and exoplanet finding. The design includes an effective straylight rejection system, however residual straylight reaches the detectors.
Aims: We test four different background models in order to apply the best possible backg…
Imaging the heliosheath using HSTOF energetic neutral atoms and Voyager 1 ion data
Hsieh, K. C.; Hilchenbach, M.; Czechowski, A. +2 more
Context: Voyager 1 and 2 LECP instruments measure the distributions of the heliosheath ions of energies ≥40 keV. This threshold energy is an order of magnitude higher than the maximum energy (6 keV) of the energetic neutral atoms (ENA) to be measured by the forthcoming IBEX mission. On the other hand, the energy range of SOHO/CELIAS/HSTOF ENA meas…