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Asiago eclipsing binaries program. I. V432 Aurigae
Munari, U.; Zwitter, T.; Sordo, R. +4 more
The orbit and physical parameters of the previously unsolved eclipsing binary V432 Aur, discovered by Hipparcos, have been derived with errors better than 1% from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral analysis of both components has been performed, yielding Teff and log g in close agreement with the orbi…
The morphology of cometary X-ray emission
Dennerl, K.; Wegmann, R.; Lisse, C. M.
X-ray emission from comets is generated by charge exchange of heavy solar wind ions in a high ionization state with the neutral particles of the cometary coma. We use model calculations and theoretical considerations to study the morphology of the emission. The emission is located in a bowl-shaped region on the subsolar side of the nucleus. We der…
Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona?
Solanki, S. K.; Raouafi, N. -E.
Coronagraphic spectral observations carried out with UVCS on SoHO have shown that the velocity distribution in the solar corona is highly anisotropic. Here we examine the influence of the density stratification on the interpretation of such observations. In particular, we investigate the profiles of O VI lines emitted in the corona by employing an…
Astrophysical lasers operating in optical Fe II lines in stellar ejecta of η Carinae
Johansson, S.; Letokhov, V. S.
After the discovery of space masers based on OH radicals (Weaver et al. \cite{Wea65}) and H2O (Cheung et al. \cite{Che69}) such microwave lasers have been found to work in more than 100 molecular species (Elitzur \cite{Eli92}; Townes \cite{Tow97}), as well as in highly excited H atoms (Strelnitski et al. \cite{Str96}). In the IR region …
The XMM-Newton view of NGC 6251
Brandt, W. N.; Mushotzky, R.; Gliozzi, M. +2 more
We report on the nuclear X-ray properties of the radio galaxy
A search for clusters and groups of galaxies on the line of sight towards 8 lensed quasars
Faure, C.; Alloin, D.; Kneib, J. P. +1 more
In this paper we present new ESO/VLT FORS1 and ISAAC images of the fields around eight gravitationally lensed quasars: CTQ 414, HE 0230-2130, LBQS 1009-0252, B 1030+074, HE 1104-1805, B 1359+154, H 1413+117 and HE 2149-2745. When available and deep enough, HST/WFPC2 data were also used to infer the photometric redshifts of the galaxies around the …
Quasi-simultaneous XMM-Newton and VLA observation of the non-thermal radio emitter HD 168112 (O5.5III(f+))
Blomme, R.; Rauw, G.; De Becker, M. +8 more
We report the results of a multiwavelength study of the non-thermal radio emitter HD 168112 (O5.5III(f+)). The detailed analysis of two quasi-simultaneous XMM-Newton and VLA observations reveals strong variability of this star both in the X-ray and radio ranges. The X-ray observations separated by five months reveal a decrease of the X-…
A large X-ray flare from the Herbig Ae star V892 Tau
Micela, G.; Favata, F.; Giardino, G. +1 more
We report the XMM-Newton observation of a large X-ray flare from the Herbig Ae star V892 Tau. The apparent low mass companion of V892 Tau, V892 Tau NE, is unresolved by XMM-Newton. Nevertheless there is compelling evidence from combined XMM-Newton and Chandra data that the origin of the flare is the Herbig Ae star V892 Tau. During the flare the X-…
X-ray spectroscopy of the Hertzsprung-gap giant star 31 Com, observed with XMM-Newton
Peres, G.; Maggio, A.; Scelsi, L. +1 more
We have analysed the XMM-Newton X-ray spectra of the yellow giant 31 Com with the aim of deriving information on the coronal structures of this archetypical Hertzsprung-gap star. To determine the emission measure distribution vs. temperature, EM(T), and the elemental abundances of the coronal plasma, with an accurate line-based approach, we have d…
The reprocessing features in the X-ray spectrum of the NELG MCG -5-23-16
Bianchi, S.; Balestra, I.; Matt, G.
We present results from the spectral analysis of the Seyfert 1.9 galaxy MCG -5-23-16, based on ASCA, BeppoSAX, Chandra and XMM-Newton observations. The spectrum of this object shows a complex iron Kα emission line, which is best modeled by a superposition of a narrow and a broad (possibly relativistic) iron line, together with a Compton reflection…