Related papers: Modeling X-ray Emission Line Profiles from Massive…
Identifying trends between observational data and the range of physical parameters of massive stars is a critical step to the still-elusive full understanding of the source, structure, and evolution of X-ray emission from the stellar winds,…
It is commonly adopted that X-rays from O stars are produced deep inside the stellar wind, and transported outwards through the bulk of the expanding matter which attenuates the radiation and affects the shape of emission line profiles.…
We consider the consequences of appreciable line optical depth for the profile shape of X-ray emission lines formed in stellar winds. The hot gas is thought to arise in distributed wind shocks, and the line formation is predominantly via…
Winds are an important ingredient in the evolution of X-ray binary (XRB) systems, particularly those at high accretion rates such as ultra-luminous X-ray sources (ULXs), because they may regulate the accretion of matter onto the compact…
We present a simple analysis of X-ray emission and absorption for hot-star winds, designed to explore the natural scalings of the observed X-ray luminosity with wind and sstellar properties. We show that an exospheric approximation, in…
Most types of massive stars display X-ray emission that is affected by the properties of their stellar winds. Single non-magnetic OB stars have an X-ray luminosity that scales with their bolometric luminosity and their emission is thought…
We quantitatively investigate the extent of wind absorption signatures in the X-ray grating spectra of all non-magnetic, effectively single O stars in the Chandra archive via line profile fitting. Under the usual assumption of a spherically…
Star-forming regions have been the targets of X-ray observations since the dawn of satellite X-ray astronomy. The increase in sensitivity and/or spatial resolution offered by XMM-Newton and Chandra allows a dramatic improvement, both…
The excellent sensitivity of X-ray telescopes, such as Chandra and XMM-Newton, is ideal for the study of cooling neutron stars, which can emit at these energies. In order to exploit the wealth of information contained in the high quality…
High-resolution X-ray spectra of O-type stars revealed less wind absorption than expected from smooth winds with conventional mass-loss rates. Various solutions have been proposed, including porous winds, optically thick clumps or an…
We investigate the degree to which the nearly symmetric form of X-ray emission lines seen in Chandra spectra of early-type supergiant stars could be explained by a possibly porous nature of their spatially structured stellar winds. Such…
Photospheric radius expansion during X-ray bursts can be used to measure neutron star radii and help constrain the equation of state of neutron star matter. Understanding the stellar wind dynamics is important for interpreting observations.…
X-rays give direct evidence of instabilities, time-variable structure, and shock heating in the winds of O stars. The observed broad X-ray emission lines provide information about the kinematics of shock-heated wind plasma, enabling us to…
Observational programmes currently underway with both Chandra and XMM-Newton are set to revolutionize our view of our own Galaxy. This is fortunate since the X-ray band can provide crucial diagnostics in the quest to understand the…
Mass loss is a key process in the evolution of massive stars, and must be understood quantitatively to be successfully included in broader astrophysical applications. In this review, we discuss various aspects of radiation driven mass loss,…
Planetary nebulae (PNe) are an exciting addition to the zoo of X-ray sources. Recent Chandra and XMM-Newton observations have detected diffuse X-ray emission from shocked fast winds in PN interiors as well as bow-shocks of fast collimated…
Stellar winds of massive stars are known to be driven by line absorption of UV photons, a mechanism which is prone to instabilities, causing the wind to be clumpy. The clumpy structure hampers wind mass-loss estimates, limiting our…
X-ray line profiles represent a new way of studying the winds of massive stars. In particular, they enable us to probe in detail the wind-wind collision in colliding wind binaries, providing new insights into the structure and dynamics of…
The past decade has seen a large progress in the X-ray investigation of early-type galaxies of the local universe, and first attempts have been made to reach redshifts z>0 for these objects, thanks to the high angular resolution and…
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…