Related papers: Radio emission models of Colliding-Wind Binary Sys…
With their emission-line dominated spectra, the appearance of Wolf-Rayet stars is shaped by their strong stellar winds. Yet, the physical mechanisms behind their high mass loss have long remained enigmatic. While we know nowadays that…
Motivated by recent reports of strongly correlated radio and X-ray variability in 3C279 (Grandi, etal 1995), we have computed the relative amplitudes of variations in the synchrotron flux at $\nu$ and the self-Compton X-ray flux at 1 keV…
Classical Wolf Rayet (WR) stars are direct supernova progenitors undergoing vigorous mass-loss. Understanding the dense and fast outflows of such WR stars is thus crucial for understanding advanced stages of stellar evolution, the dynamical…
The origin of chemically peculiar stars and non-zero eccentricity in evolved close binaries have been long-standing problems in binary stellar evolution. Answers to these questions may trace back to an intense mass transfer during AGB…
Large wind kinetic power of Wolf-Rayet (WR) stars make them ideal targets in low radio frequencies to search for non-thermal emission due to relativistic particle acceleration. In this paper, we present observations of two WR stars, WR 114…
Our dedicated XMM-Newton monitoring, as well as archival Chandra and Swift datasets, were used to examine the behaviour of the WN5h+O3V binary WR21a at high energies. For most of the orbit, the X-ray emission exhibits few variations.…
Unpulsed, high-energy emission from pulsar binaries can be attributed to the interaction of a pulsar wind with that of a companion star. At the shock between the outflows, particles carried away from the pulsar magnetosphere are accelerated…
I discuss some of the important aspects of the phenomena of colliding winds in massive binary star systems with a particular focus on WR140.
Wolf-Rayet stars represent one of the final stages of massive stellar evolution. Relatively little is known about this short-lived phase and we currently lack reliable mass, distance, and binarity determinations for a representative sample.…
WR 125 is considered as a Colliding Wind Wolf-rayet Binary (CWWB), from which the most recent infrared flux increase was reported between 1990 and 1993. We observed the object four times from November 2016 to May 2017 with Swift and…
We present high resolution simulations with RAMSES of supersonic colliding stellar winds. The collision results in a double shock structure which is subject to different instabilities. The Kelvin-Helmholtz instability (KHI) introduces some…
The eccentric WR+O binary system WR 140 produces dust for a few months at intervals of 7.94 yrs coincident with periastron passage. We present the first resolved images of this dust shell, at binary phases ~0.039 and ~0.055, using aperture…
We present the first non-LTE atmosphere models for WR stars that incorporate a self-consistent solution of the hydrodynamic equations. The models account for iron-group line-blanketing and clumping, and compute the hydrodynamic structure of…
We present mid-infrared (2-12 micron) spectra of the microquasar SS 433 obtained with the Infrared Space Observatory (spectroscopic mode of ISOPHOT and ISOCAM). We compare them to the spectra of four Wolf-Rayet stars: WR78, WR134, WR136,…
Context. The structure of the wind from the cool giants in symbiotic binaries carries important information for understanding the wind mass transfer to their white dwarf companions and its fuelling. Aims. In this paper, we indicate a…
Determining accurate orbits of binary stars with powerful winds is challenging. The dense outflows increase the effective photospheric radius, precluding direct observation of the Keplerian motion; instead the observables are broad lines…
The standard model for radio supernovae considers that the observed synchrotron radio emission arises from the high-energy shell that results from the strong interaction between the expanding supernova ejecta and the circumstellar medium.…
Stellar winds shape the evolution of stars through the loss of mass. In binary systems, they also shape the stars' evolution by modifying the orbit. In this paper, we use hydrodynamic simulations to study the emergence of nearly-isothermal…
Fast radio bursts (FRBs) are observed to be highly polarized. Most have high linear polarization but a small fraction show significant circular polarization. We systematically investigate a variety of polarization mechanisms of FRBs within…
Fast radio bursts (FRB) can arise from synchrotron maser emission at ultra-relativistic magnetized shocks, such as produced by flare ejecta from young magnetars. We combine PIC simulation results for the synchrotron maser with the dynamics…