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Early-type stars in the core of the young open cluster Westerlund 2 ⋆⋆⋆
Aims. The properties of the early-type stars in the core of the Westerlund 2 cluster are examined in order to establish a link bet ween the cluster and the very massive Wolf-Rayet binary WR 20a as
The Wolf-Rayet stars in the Large Magellanic Cloud - A comprehensive analysis of the WN class
Context. Massive stars, although being important building blocks of galaxies, are still not fully understood. This especially holds true for Wolf-Rayet (WR) stars with their strong mass loss, whose
Wolf—Rayet binaries in the Magellanic Clouds and implications for massive-star evolution — I. Small Magellanic Cloud
We have carried out an intensive spectroscopic campaign to search for binaries via periodic radial velocity (RV) variations among all the nitrogen-rich WN Wolf‐Rayet (WR) stars in the Small
Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. ⋆ I. The nature of the companion star
Context: The INTEGRAL mission has led to the discovery of a new type of supergiant X-ray binaries (SGXBs), whose physical properties differ from those of previously known SGXBs. Those sources are in
On the distance of GRO J1655-40
Aims. We challenge the accepted distance of 3.2 kpc of GRO J1655-40. We present VLT-UVES spectroscopic observations to estimate the absorption toward the source, and determine a maximum distance of
A historic jet-emission minimum reveals hidden spectral features in 3C 273
The observed weakness of the X-ray emission supports the hypothesis of a synchrotron self-Compton origin for the jet component and there is a clear soft-excess and evidence for a very broad iron line which could be emitted in a disk around a Kerr black hole.
Biomarkers in disk-averaged near-UV to near-IR Earth spectra using Earthshine observations ⋆
We analyse the detectability of vegetation on a global scale on Earth's surface. Considering its specific reflectance spectrum showing a sharp edge around 700 nm, vegetation can be considered as a
We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, the second planet discovered by microlensing and the first in a high-magnification event. These include
Intensity interferometry and the second-order correlation function g (2) in astrophysics
Most observational techniques in astronomy can be understood as exploiting the various forms of the first-order correlation function g (1) . As demonstrated by the Narrabri stellar intensity