Search Publications
Spectropolarimetric measurements of the mean longitudinal magnetic field of chemically peculiar stars. II. Phase relating the magnetic and luminosity variabilities
Leone, F.; Catanzaro, G.
For a sample of chemically peculiar stars, we report time-resolved measurements of the effective magnetic field which were obtained with the spectropolarimetry operating at the Catania Astrophysical Observatory. These observations are combined with data from the literature for better pointing out that periodic magnetic variability which characteri…
Analysis of blinkers and EUV brightenings in the quiet Sun observed with CDS
Solanki, S. K.; Brković, A.; Rüedi, I.
Movies of quiet Sun regions at disc centre obtained with the Coronal Diagnostic Spectrometer (CDS) onboard the SOHO spacecraft are used to study the properties of transient brightenings seen in the extreme ultraviolet (EUV), so-called blinkers, at three different temperatures sampled simultaneously in the chromospheric He I 584.3 Å (2 x 104
Large scale ionization of the Radio Arc region by the Quintuplet and the Arches clusters
Rodríguez-Fernández, N. J.; Martín-Pintado, J.; de Vicente, P.
We present an analysis of selected fine structure lines (Ne Ii 12.8 mu m, Ne IiI 15.6 mu m, S Iii 18.7 and 33.5 mu m, O Iii 52 and 88 mu m, N Ii 122 mu m and N IiI 57 mu m) observed with the Infrared Space Observatory (ISO) toward the Radio Arc in the Galactic center region (GCR). Most of the data were retrieved from the ISO Data Archive. We study…
Interpretation of coronal off-limb spectral line width measurements
Moran, T. G.
Spectral line widths measured above the solar limb have been used to infer wave velocity amplitude height dependencies, supporting Alfven wave coronal heating and wave driven solar wind models. Comparison of the inferred amplitude/density dependence with a constant magnetic field strength, undamped wave propagation model have shown good agreement,…
Simultaneous XMM-Newton and BeppoSAX observation of the Seyfert I galaxy IC 4329A
Gondoin, P.; Parmar, A. N.; Oosterbroek, T. +3 more
We report on a simultaneous XMM-Newton and BeppoSAX observation of the Seyfert 1 galaxy IC 4329A performed in 2001 January. Above 1 keV, EPIC spectra show a narrow Fe K emission line at 6.42+0.04-0.03 keV with an equivalent width of 43+/-1 eV. An absorption edge is detected at 7.1+/-0.4 keV in the source rest frame that has n…
On the nature of the hard X-ray source 4U 2206+54
Reig, P.; Negueruela, I.
The recent discovery of a ~ 9.5\:d period in the X-ray lightcurve of the massive X-ray binary
First XMM-Newton observations of a cataclysmic variable I: Timing studies of OY Car
Priedhorsky, W.; Pandel, D.; Ramsay, G. +9 more
We present XMM-Newton observations of the eclipsing, disc accreting, cataclysmic variable OY Car which were obtained as part of the performance verification phase of the mission. The star was observed 4 days after an outburst and then again 5 weeks later when it was in a quiescent state. There is a quasi-stable modulation of the X-rays at ~ 2240 s…
SOHO/SUMER observations and analysis of the hydrogen Lyman spectrum in solar prominences
Heinzel, P.; Vial, J. -C.; Schmieder, B. +1 more
The complete hydrogen Lyman spectrum in several prominences has been observed with the UV spectrometer SUMER on-board the SOHO, during the Joint Observing Programme 107, together with other space and ground-based observatories. Based on these observations, we are able to demonstrate, for the first time, that there exists a large variety of intensi…
Multi-colour light variation of AGB stars observed with ISO
Lebzelter, T.; Kerschbaum, F.; Lazaro, C.
New visual light curves and infrared multi-epoch photometry are presented for a sample of AGB-stars spectroscopically observed with ISO. While the ISO work is or will be presented elsewhere, the aim of this paper is to give an overview of the properties of the light change of the objects. This information is crucial for the interpretation of the v…
XMM-Newton observation of the Seyfert 1 galaxy Fairall 9
Gondoin, P.; Guainazzi, M.; Schartel, N. +2 more
We report an X-ray observation of the Fairall 9 Seyfert 1 galaxy performed in July 2000 with the EPIC cameras and Reflection Grating Spectrometers (RGS) on board the XMM-Newton observatory. Above 2 keV, the high signal to noise ratio of the EPIC spectra shows an emission line at 6.38+/-0.03 keV with a measured equivalent width of 120 eV. An absorp…