Related papers: Clumping effects on non-thermal particle spectra i…
Binary systems that host a massive star and a non-accreting pulsar can be powerful non-thermal emitters. The relativistic pulsar wind and the non-relativistic stellar outflows interact along the orbit, producing ultrarelativistic particles…
We present the results of numerical simulations of continuum-driven winds of stars that exceed the Eddington limit and compare these against predictions from earlier analytical solutions. Our models are based on the assumption that the…
A small fraction of the radiative flux emitted by hot stars is absorbed by their winds and redistributed towards longer wavelengths. This effect, which leads also to the heating of the stellar photosphere, is termed wind blanketing. For…
We present the first systematic spectropolarimetric study of Luminous Blue Variables (LBVs), and find that at least half those objects studied display evidence for intrinsic polarization -- a signature of significant inhomogeneity at the…
Several gamma-ray binaries show extended X-ray emission that may be associated to interactions of an outflow with the medium. Some of these systems are, or may be, high-mass binaries harboring young nonaccreting pulsars, in which the…
Results of a study of the theoretically predicted and observed X-ray properties of local massive star clusters are presented, with a focus on understanding the mass and energy flow from these clusters into the ISM via a cluster wind. A…
Non-thermal emission has been detected in WR-stars for many years at long wavelengths spectral range, in general attributed to synchrotron emission. Two key ingredients are needed to explain such emissions, namely magnetic fields and…
Towards the end of their evolution hot massive stars develop strong stellar winds and appear as emission line stars, such as WR stars or LBVs. The quantitative description of the mass loss in these important pre-SN phases is hampered by…
We discuss recent evidence that currently accepted mass-loss rates may need to be revised downwards, as a consequence of previously neglected ``clumping'' of the wind. New results on the radial stratification of the corresponding clumping…
The central regions of galaxies are complex environments, rich in evolved and/or massive stars. For galaxies hosting an active galactic nucleus (AGN) with jets, the interaction of the jets with the winds of the stars within can lead to…
We present Monte Carlo radiative transfer simulations for spiral galaxies modelled as a stellar disk and a two-phase clumpy dust distribution. We divide the volume occupied by the dust into a three-dimensional grid and assign each cell a…
Star clusters larger than $\sim 10^{3}$ $M_\odot$ contain multiple hot stars that launch fast stellar winds. The integrated kinetic energy carried by these winds is comparable to that delivered by supernova explosions, suggesting that at…
Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may…
The recently discovered massive binary system Apep is the most powerful synchrotron emitter among the known Galactic colliding-wind binaries. This makes this particular system of great interest to investigate stellar winds and the…
Colliding winds of massive binaries have long been considered as potential sites of non-thermal high-energy photon production. This is motivated by the detection of non-thermal spectra in the radio band, as well as by correlation studies of…
Starforming factories in galaxies produce compact clusters and loose associations of young massive stars. Fast radiation-driven winds and supernovae input their huge kinetic power into the interstellar medium in the form of highly…
INTEGRAL, the European Space Agency's gamma-ray observatory, tripled the number of super-giant high-mass X-ray binaries (sgHMXB) known in the Galaxy by revealing absorbed and fast transient (SFXT) systems. In these sources, quantitative…
Massive stars feature highly energetic stellar winds that interact whenever two such stars are bound in a binary system. The signatures of these interactions are nowadays found over a wide range of wavelengths, including the radio domain,…
We review the possible roles of large scale shocks as particle accelerators in clusters of galaxies. Recent observational and theoretical work has suggested that high energy charged particles may constitute a substantial pressure component…
Several recent observational studies have shown that the clustering of young stars in local star-forming regions, and of Cepheids in the LMC, can be described by a power law two-point correlation function. We show by numerical simulations…