Search Publications
Photometric properties of facular features over the activity cycle
Ermolli, I.; Giorgi, F.; Criscuoli, S. +2 more
Aims:We have analyzed the contrast of facular features identified in a large dataset of PSPT full-disk photometric images and SoHO/MDI magnetograms, obtained from 1998 to 2005. The aim of this work is to contribute to the improvement of semi-empirical atmospheric models and of irradiance studies and to understand the reasons for the controversial …
XMM-Newton broad-band observations of NGC 7582: N{H} variations and fading out of the active nucleus
Fiore, F.; Bianchi, S.; Guainazzi, M. +2 more
We present results from two XMM-Newton observations of the bright classical Seyfert 2 galaxy NGC 7582 taken four years apart (2001 May and 2005 April). We present the analysis of the high-resolution (0.3-1 keV) RGS and low-resolution (0.3-10 keV) EPIC spectroscopic data. A comparison with a 1998 BeppoSAX observation suggests that XMM-Newton caught…
Formation of Titan in Saturn's subnebula: constraints from Huygens probe measurements
Alibert, Y.; Mousis, O.
We present an evolutionary turbulent model of the Saturn's subnebula consistent with recent core accretion formation models of Saturn. Our calculations are similar to those conducted in the case of the Jovian subnebula, and take into account the vertical structure of the disk, as well as the evolution of its surface density, as given by an α-disk …
X-ray emission from the stellar population in M 32
Revnivtsev, M.; Sazonov, S.; Churazov, E. +2 more
Using Chandra observations, we study the X-ray emission of the stellar population in the compact dwarf elliptical galaxy M 32. The proximity of M 32 allows one to resolve all bright point sources with luminosities higher than 8×1033~erg~s-1 in the 0.5-7 keV band. The remaining (unresolved) emission closely follows the galaxy'…
The molecular and dusty composition of Betelgeuse's inner circumstellar environment
Nguyen, Q. N.; Lopez, B.; Leinert, Ch. +6 more
Context: The study of the atmosphere of red supergiant stars in general and of
Aims: A molecular shell, the MOLsphere (Tsuji 2000a, ApJ, 538, 80…
Projection effects in coronal mass ejections
Vršnak, B.; Žic, T.; Sudar, D. +1 more
Context: Basic observational parameters of a coronal mass ejection (CME) are its speed and angular width. Measurements of the CME speed and angular width are severely influenced by projection effects.
Aims: The goal of this paper is to investigate a statistical relationship between the plane-of-sky speeds of CMEs and the direction of their pro…
Energetics of solar coronal mass ejections
Vourlidas, A.; Subramanian, P.
Aims:We investigate whether solar coronal mass ejections are driven mainly by coupling to the ambient solar wind or through the release of internal magnetic energy.
Methods: We examine the energetics of 39 flux-rope like coronal mass ejections (CMEs) from the Sun using data in the distance range ~2-20 R⊙ from the Large Angle Spectro…
Presence of dust with a UV bump in massive, star-forming galaxies at 1 < z < 2.5
Pannella, M.; Noll, S.; Pierini, D. +1 more
Aims:Fundamental properties of the extinction curve, like the slope in the rest-frame ultraviolet (UV) and the presence/absence of a broad absorption excess centred at 2175 Å (the UV bump), are investigated for a sample of 108 massive, star-forming galaxies at 1 < z < 2.5, selected from the FDF Spectroscopic Survey, the K20 survey, and the G…
Properties of prominence fine-structure threads derived from SOHO/SUMER hydrogen Lyman lines
Heinzel, P.; Anzer, U.; Schmieder, B. +2 more
Context: The SOHO/SUMER observations provide us for the first time with the prominence spectra in the Lyman-α line outside the attenuator together with the higher members of the hydrogen Lyman series.
Aims: We derive the prominence fine-structure thread properties by comparing the SOHO/SUMER hydrogen Lyman series observations with the syntheti…
Exploring the connection between the stellar wind and the non-thermal emission in LS 5039
Motch, C.; Janot-Pacheco, E.; Negueruela, I. +5 more
Context: LS 5039 has been observed with several X-ray instruments so far showing quite steady emission in the long term and no signatures of accretion disk. The source also presents X-ray variability at orbital timescales in flux and photon index. The system harbors an O-type main sequence star with moderate mass-loss. At present, the link between…