Search Publications
The environment of the fast rotating star Achernar. II. Thermal infrared interferometry with VLTI/MIDI
Meilland, A.; Kervella, P.; Domiciano de Souza, A. +3 more
Context: As is the case of several other Be stars, Achernar is surrounded by an envelope, recently detected by near-IR interferometry.
Aims: We search for the signature of circumstellar emission at distances of a few stellar radii from Achernar, in the thermal IR domain.
Methods: We obtained interferometric observations on three VLTI basel…
Redshifts and lens profile for the double quasar QJ 0158-4325
Kneib, J. -P.; Faure, C.; Alloin, D. +5 more
Aims: We report on the redshift of the lensing galaxy and of the quasar QJ 0158-4325 and on the lens model of the system.
Methods: A deep VLT/FORS2 spectrum and HST/NICMOS-F160W images are deconvolved. From the images we derive the light profile of the lensing galaxy and an accurate relative astrometry for the system. In addition we measure th…
Coronal current sheet signatures during the 17 May 2002 CME-flare
Landini, F.; Poletto, G.; Aurass, H.
Context: The relation between current sheets (CSs) associated with flares, revealed by characteristic radio signatures, and current sheets associated with coronal mass ejections (CMEs), detected in coronal ultraviolet (UV) and white light data, has not been analyzed, yet.
Aims: We aim at establishing the relationship between CSs associated wit…
Photometric and spectroscopic investigation of 2867 Steins, target of the Rosetta mission. Ground-based results prior to the Rosetta fly-by
Barucci, M. A.; Fornasier, S.; Dotto, E. +8 more
Context: Rosetta is the cornerstone mission of ESA devoted to the study of minor bodies of the Solar System. During its journey to the comet 67P Churyumov-Gerasimenko, the main target, Rosetta also investigates two main belt asteroids, 2867 Steins (fly-by in September 2008) and 21 Lutetia (fly-by in July 2010).
Aims: In Spring 2008, we perform…
The molecular environment of the massive star forming region NGC 2024: Multi CO transition analysis
Emprechtinger, M.; Stutzki, J.; Güsten, R. +10 more
Context: Sites of massive star formation have complex internal structures. Local heating by young stars and kinematic processes, such as outflows and stellar winds, generate large temperature and velocity gradients. Complex cloud structures lead to intricate emission line shapes. CO lines from high mass star forming regions are rarely Gaussian and…
Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902
Heymans, C.; Gray, M. E.; Wolf, C. +21 more
We present a study of the population of bright early-type dwarf galaxies in the multiple-cluster system Abell 901/902. We use data from the STAGES survey and COMBO-17 to investigate the relation between the color and structural properties of the dwarfs and their location in the cluster. The definition of the dwarf sample is based on the central su…
The young active star SAO 51891 (V383 Lacertae)
Frasca, A.; Biazzo, K.; Covino, E. +5 more
Aims: The aim of this work is to investigate the surface inhomogeneities of a young, late-type star, SAO 51891, at different atmospheric levels, from the photosphere to the upper chromosphere, analyzing contemporaneous optical high-resolution spectra and broad-band photometry.
Methods: The full spectral range of FOCES@CAHA (R ≃ 40 000) is used…
Simulation of a flux emergence event and comparison with observations by Hinode
Solanki, S. K.; Lagg, A.; Cheung, M. C. M. +2 more
Aims: We study the observational signature of flux emergence in the photosphere using synthetic data from a 3D MHD simulation of the emergence of a twisted flux tube.
Methods: Several stages in the emergence process are considered. At every stage we compute synthetic Stokes spectra of the two iron lines Fe I 6301.5 Å and Fe I 6302.5 Å and degr…
Analysis of extremely low signal-to-noise ratio data from INTEGRAL/PICsIT
Lubiński, P.
Context: The PICsIT detector onboard the INTEGRAL satellite was designed to provide information about emission in the soft γ-ray band for many bright sources. Due to strong and variable instrumental background, only 4 objects have been detected so far using standard software.
Aims: The moderate sensitivity of PICsIT can be compensated for in t…
Discovery of a rapidly pulsating subdwarf B star candidate in ω Centauri
Bono, G.; Calamida, A.; Randall, S. K.
We report the discovery of the first variable extreme horizontal branch star in a globular cluster (ω Cen). The oscillation uncovered has a period of 114 s and an amplitude of 32 mmag. A comparison between horizontal branch models and observed optical colours indicates an effective temperature of 31 500 ± 6300 K for this star, placing it within th…