Related papers: Runaway massive stars as variable gamma-ray source…
A long standing problem in high energy astrophysics is the nature of galactic accelerators of particles with energies above PeV. Such objects are sources of galactic cosmic rays and can produce PeV-regime photons observed by ground-based…
We investigate the connections between the magnetic fields and the X-ray emission from massive stars. Our study shows that the X-ray properties of known strongly magnetic stars are diverse: while some comply to the predictions of the…
Young massive stars in the halo are assumed to be runaway stars from the Galactic disk. Possible ejection scenarios are binary supernova ejections (BSE) or dynamical ejections from star clusters (DE). Hypervelocity stars (HVSs) are extreme…
We model how repeated supernova explosions in high-redshift dwarf starburst galaxies drive superbubbles and winds out of the galaxies. We compute the efficiencies of metal and mass ejection and energy transport from the galactic potentials,…
Non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. We present X-ray observations towards the runaway stars $\zeta$ Oph (Chandra and Suzaku) and BD+43$^{\circ}$3654 (XMM-Newton) to…
(abridged) Non-degenerate stars of essentially all spectral classes are soft X-ray sources. Low-mass stars on the cooler part of the main sequence and their pre-main sequence predecessors define the dominant stellar population in the galaxy…
In this contribution I summarize our current knowledge of the nature and significance of starburst-driven galactic superwinds. These flows are driven primarily by the kinetic energy supplied by supernovae. Superwinds are complex, multiphase…
The circumstellar medium around massive stars is strongly impacted by stellar winds, radiation, and explosions. We use numerical simulations of these interactions to constrain the current properties and evolutionary history of various stars…
We consider spherical stellar clusters with a broad mass function and a relaxation time short enough so that the segregation of massive stars toward the centre occurs before they have time to evolve off the main sequence. The relaxational…
The motions of comets and neutron stars have been integrated over five billion years in the Galactic potential to determine a gamma-ray burst distribution, presuming that bursts are the result of interactions between these two families of…
Intermediate-mass stars end their lives by ejecting the bulk of their envelope via a slow dense wind back into the interstellar medium, to form the next generation of stars and planets. Stellar pulsations are thought to elevate gas to an…
Collapsing massive stars lead to a broad range of astrophysical transients, whose multi-wavelength emission is powered by a variety of processes including radioactive decay, activity of the central engine, and interaction of the outflows…
Some runaway stars are known to display IR arc-like structures around them, resulting from their interaction with surrounding interstellar material. The properties of these features as well as the processes involved in their formation are…
The successful discovery of X-ray, optical and radio afterglows of gamma-ray bursts has significantly helped our understanding of these sources, and made possible the identification of host galaxies at cosmological distances. The energy…
Moderately strong shocks arise naturally when two subclusters merge. For instance, when a smaller subcluster falls into the gravitational potential of a more massive cluster, a bow shock is formed and moves together with the subcluster.…
We report the discovery of six infrared stellar-wind bowshocks in the Galactic massive star formation regions M17 and RCW49 from Spitzer GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) images. The InfraRed Array Camera…
Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are…
We continue our numerical analysis of the morphological and energetic influence of massive stars on their ambient interstellar medium for a 35 solar mass star that evolves from the main sequence through red supergiant and Wolf-Rayet phases,…
With the exception of the Big Bang, responsible for 1,2H, 3,4He, and 7Li, stars act as sources for the composition of the interstellar medium. Cosmic rays are related to the latter and very probably due to acceleration of the mixed…
We have determined mass loss rates and gas expansion velocities for a sample of 69 M-type irregular (IRV; 22 objects) and semiregular (SRV; 47 objects) AGB-variables using a radiative transfer code to model their circumstellar CO radio line…