Search Publications
Hot and cool: two emission-line stars with constrasting behaviours in the same XMM-Newton field
Nazé, Y.; Rauw, G.; Ud-Doula, A.
High-energy emissions are good indicators of peculiar behaviours in stars. We have therefore obtained an XMM-Newton observation of HD 155806 and 1RXS J171502.4-333344, and derived their spectral properties for the first time. The X-ray spectrum of HD 155806 appears soft, even slightly softer than usual for O-type stars (as shown by a comparison wi…
Astrometry with Carte du Ciel plates, San Fernando zone . II. CdC-SF: a precise proper motion catalogue
Girard, T. M.; Abad, C.; Vicente, B. +1 more
Context. The historic plates of the Carte du Ciel, an international cooperative project launched in 1887, offer valuable first-epoch material for the determination of absolute proper motions.
Aims: We present the CdC-SF, an astrometric catalogue of positions and proper motions derived from the Carte du Ciel plates of the San Fernando zone, ph…
Properties of active galactic star-forming regions probed by imaging spectroscopy with the Fourier transform spectrometer (FTS) onboard AKARI
Takahashi, H.; Nakagawa, T.; Okada, Y. +8 more
Aims: We investigate the structure of the interstellar medium (ISM) and identify the location of possible embedded excitation sources from far-infrared (FIR) line and mid-infrared continuum emission maps.
Methods: We carried out imaging spectroscopic observations of four giant Galactic star-forming regions with the Fourier transform spec…
Optically faint X-ray sources in the Chandra deep field North: Spitzer constraints
Georgantopoulos, I.; Rovilos, E.; Fotopoulou, S. +1 more
We investigate the properties of the most optically faint sources in the GOODS-N area (RAB > 26.5). These extremely optically faint populations present an uncharted territory although they represent an appreciable fraction of the X-ray sources in the GOODS-N field. The optically faint sources are believed to contain either red active…
The SUMER Ly-α line profile in quiescent prominences
Curdt, W.; Teriaca, L.; Tian, H. +1 more
Aims: As the result of a novel observing technique, we publish for the first time SoHO-SUMER observations of the true spectral line profile of hydrogen Lyman-α in quiescent prominences. Because SoHO is not in Earth orbit, our high-quality data set is free of geocoronal absorption. We studied the line profile to complement earlier observations…
Global plasma-parameter simulation of Comet 67P/Churyumov-Gerasimenko approaching the Sun
Glassmeier, K. -H.; Kührt, E.; Motschmann, U. +4 more
We simulate the evolution of the plasma environment of comet 67P/Churyumov-Gerasimenko (CG), which is the target comet of the European Space Agency's (ESA) Rosetta mission, as the comet approaches the Sun. The plasma environment is calculated in three dimensions with a hybrid plasma model. The model treats the dynamics of the solar wind protons an…
Separating inner and outer contributions in gravitational lenses with the perturbative method
Alard, C.
Context. This paper presents a reconstruction of the gravitational lens SL2S02176-0513 with the singular perturbative method presented in Alard (2007, MNRAS, 382, L58) and Alard (2008, MNRAS, 388, 375).
Aims: The ability of the perturbative method to separate the inner and outer contributions of the potential in gravitational lenses is tested…
Updated phase coherent timing solution of the isolated neutron star RX J0720.4-3125 using recent XMM-Newton and Chandra observations
Haberl, F.; de Vries, C. P.; Vink, J. +4 more
Aims: Since the last phase coherent timing solution of the nearby radio-quiet isolated neutron star RX J0720.4-3125 six new XMM-Newton and three Chandra observations were carried out. The phase coherent timing solutions from previous authors were performed without restricting to a fixed energy band. However, we recently showed that the phase …
Post-flare evolution of AR 10923 with Hinode/XRT
Parenti, S.; Reale, F.; Reeves, K. K.
Context. Flares are dynamic events which involve rapid changes in coronal magnetic topology end energy release. Even if they may be localized phenomena, the magnetic disturbance at their origin may propagate and be effective in a larger part of the active region.
Aims: We investigate the temporal evolution of a flaring active region with resp…
Periodic variability in the emission spectrum of T Tauri
Ismailov, N. Z.; Quliev, N. K.; Khalilov, O. V. +1 more
Context. Long timescale periodic variations in T Tauri stars may be related to changes in their protoplanetary disks.
Aims: A lengthy homogeneous series of spectral observations of the CTTS T TauN has been analyzed.
Methods: We search for periodicity in the equivalent widths of the emission lines in the optical and in the UV.
Result…