Related papers: Gamma Rays from colliding winds in massive binarie…

We have compiled a list of 36 O+O and 89 Wolf-Rayet binary candidates in the Milky Way and Magellanic clouds detected with the Chandra, XMM-Newton and ROSAT satellites to probe the connection between their X-ray properties and their system…

At least one massive binary system containing an energetic pulsar, PSR B1259-63/SS2883, has been recently detected in the TeV gamma-rays by the HESS telescopes. These gamma-rays are likely produced by particles accelerated in the vicinity…

Recent IR observations indicate that many massive binary systems present dust formation episodes, in regions close to the stars, during the periastron passage. These systems are known to be high-energy sources, and it is believed that wind…

We discuss X-ray line formation in dense O star winds. A random distribution of wind shocks is assumed to emit X-rays that are partially absorbed by cooler wind gas. The cool gas resides in highly compressed fragments oriented perpendicular…

We present the results of an intensive spectroscopic campaign in the optical waveband revealing that Cyg OB2 #8A is an O6 + O5.5 binary system with a period of about 21.9 d. Cyg OB2 #8A is a bright X-ray source, as well as a non-thermal…

We present radio observations of the unique, recently formed, planetary nebula (PN) associated with a very long-period OH/IR variable star V1018 Sco that is unequivocally still in its asymptoticgiant branch phase. Two regions within the…

X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and X-ray observations have led to the presumption that some X-ray binaries called microquasars behave as scaled down active…

High-mass microquasars are binary systems composed by a massive star and a compact object from which relativistic jets are launched. Regarding the companion star, observational evidence supports the idea that winds of hot stars are formed…

We examine a variety of observations that shed light on the orientation of the semi-major axis of the Eta Carinae massive binary system. Under several assumptions we study the following observations: The Doppler shifts of some He I P-Cygni…

A growing number of early Be stars discovered in X-ray surveys exhibit X-ray luminosities intermediate between those of normal stars and those of most Be/X-ray binaries in quiescence. Their X-ray spectra are also much harder than those of…

Dense wind of a massive star can be partially captured by a neutron star (NS) inside a compact binary system. Depending on the parameters of NS and the wind, the matter can penetrate the inner NS magnetosphere. At some distance from the NS…

A review of spectroscopic results obtained from Chandra High Energy Transmission Grating Spectrometer and XMM-Newton Reflection Grating Spectrometer observations of several wind-fed high-mass X-ray binaries (HMXBs) is presented. These…

During its first 2 years of operation, the gamma-ray AGILE satellite accumulated an extensive dataset for the Galactic plane. The data have been monitored for transient sources and several gamma-ray sources were detected. Their variability…

Massive hot stars produce dense ultraviolet (UV) photon fields in their surroundings. If a very high-energy (VHE) gamma-ray emitter is located close to the star, then gamma-rays are absorbed in the stellar photon field, creating secondary…

Starburst galaxies have a highly increased star-formation rate compared to regular galaxies and inject huge amounts of kinetic power into the interstellar medium via supersonic stellar winds, and supernova explosions. Supernova remnants,…

X-ray and gamma-ray binaries are systems consisting of a compact object and normally a non-degenerate companion star. Most of these sources have been shown to emit radiation in a broad frequency range, from radio up to X-rays and sometimes…

The binary stellar system $\eta$ Carinae is one of very few established astrophysical hadron accelerators. It seems likely that at least some fraction of the accelerated particles escape from the system. Copious target material for hadronic…

Non-thermal hard X-ray and high-energy (HE; 1 MeV < E < 100 GeV) gamma-ray emission in the direction of Eta Carinae has been recently detected using the INTEGRAL, AGILE and Fermi satellites. This emission has been interpreted either in the…

The association of a supernova with a gamma-ray burst (GRB 030329) implies a massive star progenitor, which is expected to have an environment formed by pre-burst stellar winds. Although some sources are consistent with the expected wind…

Binaries with hot massive components are strong X-ray sources. Besides the intrinsic X-ray emission of individual binary members originating in their winds, X-ray emission stems from the accretion on the compact companion or from wind…