Search Publications
On the formation and evolution of magnetic chemically peculiar stars in the solar neighborhood
Paunzen, E.; Maitzen, H. M.; Pöhnl, H.
In order to put strict observational constraints on the evolutionary status of the magnetic chemically peculiar stars (CP2) of the upper main sequence, we have investigated a well established sample of galactic field CP2 objects within a radius of 200 pc from the Sun in the (X,Y) plane. In total, 182 stars with accurate parallax measurements from …
A new infrared view of evolved stars in IZw 18
Östlin, G.; Mouhcine, M.
We report results from near-infrared imaging of IZw 18, the most metal-poor galaxy in the local universe, with NICMOS on board the Hubble Space Telescope (HST). Observations were obtained in the broad F205W filter (~K) and in the medium-wide bands F171M and F180M, the latter which cover strong molecular absorption features in cool stars. The new d…
FIRBACK. IV. Towards the nature of the 170 µm source population
Dole, H.; Lagache, G.; Vaccari, M. +5 more
We present a detailed study of the brighter (>4σ detections) sources in the 170 µm FIRBACK northern N1 ISO survey, with the help of complementary data in the optical, radio, and mid-IR domain. For 82% of them, an optical galaxy counterpart is identified, either as the unique source of the IR emission, or as part of a multiple identificati…
Thermal and non-thermal effects driven by magnetic reconnections observed in a confined flare
Schmieder, B.; Li, H.; Berlicki, A.
In order to better understand the energy processes occurring during the impulsive phase of solar flares we compare observations with our magnetic model calculations. We study the 1N/M1.9 confined flare of 20 October 2003 observed during a Joint Observation Program (JOP157), and concentrate on the spectral analysis of the Reuven Ramaty High Energy …
INTEGRAL broadband X-ray spectrum of the intermediate polar V709 Cassiopeiae
Bonnet-Bidaud, J. M.; Falanga, M.; Suleimanov, V.
We present the hard X-ray time-averaged spectrum of the intermediate polar V709 Cas observed with INTEGRAL. We performed the observation using data from the IBIS/ISGRI instrument in the 20-100 keV energy band and from JEM-X at lower energy (5-20 keV). Using different multi-temperature and density X-ray post-shock models we measured an improved pos…
Fe VII lines in the spectrum of RR Telescopii
Young, P. R.; Lobel, A.; Berrington, K. A.
Thirteen transitions within the ground 3d2 configuration of Fe vii are identified in ultraviolet and optical spectra of the symbiotic star RR Telescopii obtained with the STIS instrument of the Hubble Space Telescope. The line fluxes are compared with theoretical data computed with the recent atomic data of Berrington et al., and high r…
X-ray spectral and timing characteristics of the stars in the young open cluster IC 2391
Micela, G.; Peres, G.; Sciortino, S. +2 more
We present X-ray spectral and timing analysis of members of the young open cluster IC 2391 observed with the XMM-Newton observatory. We detected 99 X-ray sources by analysing the summed data obtained from MOS1, MOS2 and pn detectors of the EPIC camera; 24 of them are members, or probable members, of the cluster. Stars of all spectral types have be…
Forward modeling of coronal funnels
Peter, H.; Aiouaz, T.; Keppens, R.
We propose a forward modeling approach of coronal funnels to investigate the outer layers of the solar atmosphere with respect to their thermodynamical properties and resulting emission line spectra. We investigate the plasma flow out of funnels with a new 2D MHD time dependent model including the solar atmosphere all the way from the chromosphere…
XMM-Newton observations of β Centauri (B1 III): The temperature structure in the hot plasma and the photosphere-wind connection
Raassen, A. J. J.; Mewe, R.; Cassinelli, J. P. +2 more
We present XMM-Newton observations of the B giant β Centauri (B1 III). The spectra are rich of spectral lines from a wide range of ionization stages which indicate temperatures in the range ~0.1-0.6 keV. Simultaneous fits to the rgs, epic-mos, and epic-pn spectra yield three plasma temperatures (0.1, 0.2, and 0.6 keV), emission measures, and eleme…
Classical novae in outburst: evolution of the ultraviolet emission lines in CO novae
Altamore, A.; González-Riestra, R.; Cassatella, A.
A comparative study is made of the temporal changes of the ionization level in seven CO novae well monitored with the IUE satellite at low resolution. The investigation is based on the evolution of the fluxes in eight strong ultraviolet emission lines covering a wide range of ionization potentials, from Mg II (7.6 eV) to N V (77.5 eV). We find tha…