Search Publications
Metal abundances in the cool cores of galaxy clusters
Molendi, S.; de Grandi, S.
We use XMM-Newton data to carry out a detailed study of the Si, Fe and Ni abundances in the cool cores of a representative sample of 26 local clusters. We performed a careful evaluation of the systematic uncertainties related to the instruments, the plasma codes and the spectral modeling, finding that the major source of uncertainty is the plasma …
Statistical equilibrium of silicon in the atmospheres of metal-poor stars
Zhao, G.; Mashonkina, L.; Shi, J. R. +1 more
Aims: The statistical equilibrium of neutral and ionized silicon in the atmospheres of metal-poor stars is discussed. Non-local thermodynamic equilibrium effects (NLTE) are investigated and the silicon abundances in metal-poor stars determined.
Methods: We have used high resolution, high signal to noise ratio spectra from the UVES spectragraph…
Partially-erupting prominences: a comparison between observations and model-predicted observables
Mason, H. E.; Fletcher, L.; Qiu, J. +4 more
Aims: We investigate several partially-erupting prominences to study their relationship with other CME-associated phenomena and compare these observations with observables predicted by a model of partially-expelled-flux-ropes (Gibson & Fan 2006a, ApJ, 637, L65; 2006b, J. Geophys. Res., 111, 12103).
Methods: We studied 6 selected events wit…
Hunting high and low: XMM monitoring of the eclipsing polar HU Aquarii
Dhillon, V. S.; Marsh, T. R.; Littlefair, S. P. +5 more
Aims: We want to study the temporal and spectral behaviour of HU Aqr in the X-ray domain during different accretion states.
Methods: We obtained spectra and light curves from four different XMM-Newton pointings covering intermediate and low states. The X-ray observations were accompanied with high time resolution photometry obtained with the O…
Benchmarking atomic data for astrophysics: Fe VII and other cool lines observed by Hinode EIS
Del Zanna, G.
The EUV spectrum of ion{Fe}{vii} is reviewed, using new rates for electron impact excitation, atomic structure calculations, and experimental data. In particular, solar observations of a sunspot loop spectrum obtained from the Hinode EUV Imaging Spectrometer (EIS) are used. Previous line identifications, mostly based on laboratory data, have been …
[O I] sub-arcsecond study of a microjet from an intermediate mass young star: RY Tauri
Dougados, C.; Cabrit, S.; Ferruit, P. +2 more
Context: High-resolution studies of microjets in T Tauri stars (cTTs) reveal key information on the jet collimation and launching mechanism, but only a handful of systems have been mapped so far.
Aims: We wish to perform a detailed study of the microjet from the 2 M⊙ young star RY Tau, to investigate the influence of its higher stel…
Observations and 3D MHD simulations of a solar active region jet
Gontikakis, C.; Tsinganos, K.; Archontis, V.
Aims: We study an active region jet originating from NOAA 8531 on May 15 1999. We perform 3D MHD numerical simulations of magnetic flux emergence and its subsequent reconnection with preexisting magnetic flux. Then, we compare the physical properties of the observed jet with the reconnecting outflow produced in the numerical model.
Methods: We…
Neutral interstellar hydrogen in the inner heliosphere under the influence of wavelength-dependent solar radiation pressure
Bzowski, M.; Tarnopolski, S.
Context: With the plethora of detailed results from heliospheric missions such as Ulysses and SOHO and at the advent of the first mission dedicated to in situ studies of neutral heliospheric atoms IBEX, we have entered the era of precision heliospheric studies. Interpretation of these data requires precision modeling, with second-order effects qua…
Modelling the spectral response of the Swift-XRT CCD camera: experience learnt from in-flight calibration
Campana, S.; Cusumano, G.; Moretti, A. +11 more
Context: Since its launch in November 2004, Swift has revolutionised our understanding of gamma-ray bursts. The X-ray telescope (XRT), one of the three instruments on board Swift, has played a key role in providing essential positions, timing, and spectroscopy of more than 300 GRB afterglows to date. Although Swift was designed to observe GRB afte…
Statistics of convective collapse events in the photosphere and chromosphere observed with the Hinode SOT
Lites, B. W.; de Wijn, A. G.; Fischer, C. E. +2 more
Convective collapse, a theoretically predicted process that intensifies existing weak magnetic fields in the solar atmosphere, was first directly observed in a single event by Nagata et al. (2008, ApJ, 677, L145) using the high resolution Solar Optical Telescope (SOT) of the Hinode satellite. Using the same space telescope, we observed 49 such eve…