Search Publications
Rigorous treatment of barycentric stellar motion. Perspective and light-time effects in astrometric and radial velocity data
Lindegren, L.; Butkevich, A. G.
Context. High-precision astrometric and radial-velocity observations require accurate modelling of stellar motions in order to extrapolate measurements over long time intervals, and to detect deviations from uniform motion caused, for example, by unseen companions.
Aims: We aim to explore the simplest possible kinematic model of stellar motio…
The accretion environment in Vela X-1 during a flaring period using XMM-Newton
Wilms, J.; Torrejón, J. M.; Kretschmar, P. +8 more
We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of 3.92
The extended structure of the dwarf irregular galaxies Sextans A and Sextans B. Signatures of tidal distortion in the outskirts of the Local Group
Bellazzini, M.; Galleti, S.; Testa, V. +7 more
We present a detailed study of the stellar and H i structure of the dwarf irregular galaxies Sextans A and Sextans B, members of the NGC 3109 association. We use newly obtained deep (r ≃ 26.5) and wide-field g and r photometry to extend the surface brightness (SB) profiles of the two galaxies down to µV ≃ 31.0 mag/arcsec2
Conversion from mutual helicity to self-helicity observed with IRIS
Peter, H.; Zhang, J.; Li, L. P. +1 more
Context. In the upper atmosphere of the Sun observations show convincing evidence for crossing and twisted structures, which are interpreted as mutual helicity and self-helicity.
Aims: We use observations with the new Interface Region Imaging Spectrograph (IRIS) to show the conversion of mutual helicity into self-helicity in coronal structure…
Metal distribution in sloshing galaxy clusters: the case of A496
Molendi, Silvano; Ghizzardi, Simona; De Grandi, Sabrina
We report results from a detailed study of the sloshing gas in the core of A496. We detected the low-temperature/entropy spiral feature found in several cores. We also found that conduction between the gas in the spiral and the ambient medium must be suppressed by more than one order of magnitude compared with the Spitzer conductivity. Intriguingl…
Spectroscopy of BL Lacertae objects of extraordinary luminosity
Sbarufatti, B.; Falomo, R.; Treves, A. +1 more
Aims: We aim to determine the redshift (or stringent lower limits) of a number of bright BL Lacs objects.
Methods: We secured optical and near-infrared medium-resolution spectra of four bright BL Lac objects of unknown redshift using the spectrograph X-Shooter at the ESO-VLT.
Results: In spite of the high quality of the spectra and …
Modeling magnesium escape from HD 209458b atmosphere
Lecavelier des Etangs, A.; Bourrier, V.; Vidal-Madjar, A.
Transit observations in the Mg i line of HD 209458b revealed signatures of neutral magnesium escaping the upper atmosphere of the planet, while no atmospheric absorption was found in the Mg ii doublet. Here we present a 3D particle model of the dynamics of neutral and ionized magnesium populations, coupled with an analytical modeling of the atmosp…
The rapid evolution of the exciting star of the Stingray nebula
Rauch, T.; Werner, K.; Kruk, J. W. +5 more
Context.
Structure and substructure analysis of DAFT/FADA galaxy clusters in the [0.4-0.9] redshift range
Ilbert, O.; Schirmer, M.; Allam, S. +29 more
Context. The DAFT/FADA survey is based on the study of ~90 rich (masses found in the literature >2 × 1014 M⊙) and moderately distant clusters (redshifts 0.4 < z < 0.9), all with HST imaging data available. This survey has two main objectives: to constrain dark energy (DE) using weak lensing tomography on galaxy clust…
Warm molecular gas temperature distribution in six local infrared bright Seyfert galaxies
Spinoglio, Luigi; Pereira-Santaella, Miguel; van der Werf, Paul P. +1 more
We simultaneously analyze the spectral line energy distributions (SLEDs) of CO and H2 of six local luminous infrared (IR) Seyfert galaxies. For the CO SLEDs, we used new Herschel/SPIRE FTS data (from J = 4-3 to J = 13-12) and ground-based observations for the lower-J CO transitions. The H2 SLEDs were constructed using archiva…