Related papers: Modeling Emission-Line Surface Brightness in a Mul…
Context. The first magnetic fields in O- and B-type stars that do not belong to the Bp-star class, have been discovered. The cyclic UV wind-line variability, which has been observed in a significant fraction of early-type stars, is likely…
Context. Late O-type stars at luminosities $\log L/L_\odot \lesssim 5.2$ show weak winds with mass-loss rates lower than 10$^{-8} M_\odot$ yr$^{-1}$. This implies that their photospheric layers are not strongly affected by the stellar wind.…
Galactic outflows have density, temperature, and velocity variations at least as large as that of the multiphase, turbulent interstellar medium (ISM) from which they originate. We have conducted a suite of parsec-resolution numerical…
Blue supergiants (BSGs) are key objects for understanding the evolution of massive stars. However, discrepancies between theoretical predictions and empirical observations have opened up important questions yet to be answered. Studying…
Stellar rotation is an important parameter in the evolution of massive stars. Accurate and reliable measurements of projected rotational velocities in large samples of OB stars are crucial to confront the predictions of stellar evolutionary…
Aims: To model broad H-alpha wings observed in symbiotic binaries by an optically thin, bipolar stellar wind from their hot components as an alternative to that considering the Raman scattering of Ly-beta photons on atomic hydrogen.…
Diffuse hot gas can be traced effectively by its X-ray absorption and emission. We present a joint-analysis of these tracers to characterize the spatial and temperature distributions of the Galactic hot gas along the sight-line toward the…
We perform hydrodynamical simulations of a young galactic disc embedded in a hot gaseous halo using parameters typical for Lyman break galaxies (LBGs). We take into account the (static) gravitational potentials due to a dark matter halo, a…
New numerical models of line-driven stellar winds of late O stars are presented. Statistical equilibrium (NLTE) equations of the most abundant elements are solved. Properly obtained occupation numbers are used to calculate consistent…
A grid of models for starburst spectra is presented and compared with power-law models which represent AGNs. The models are composite, i.e., they account for the radiation from the starburst and for the shocks created by super-winds. Some…
Recent spectropolarimetric surveys (MiMeS, BOB) have revealed that approximately 7% of massive stars host stable, surface dipolar magnetic fields with strengths on the order of kG. These fields channel the dense radiatively driven stellar…
We have used the Far Ultraviolet Spectroscopic Explorer to search for OVI 1031.926, 1037.617 A emission in the halos of the edge-on spiral galaxies NGC4631 and NGC891. In NGC4631, we detected OVI in emission toward a soft X-ray bubble above…
I provide an observational review of the properties of starburst-driven galactic superwinds, focusing mainly on recent results pertinent to the transport of metals and energy into the IGM. Absorption-line studies are providing rich…
We use numerical simulations to analyze the evolution and properties of superbubbles (SBs), driven by multiple supernovae (SNe), that propagate into the two-phase (warm/cold), cloudy interstellar medium (ISM). We consider a range of mean…
We present a semi-analytical approach for modeling circumstellar emission from rotating hot stars with a strong dipole magnetic field tilted at an arbitrary angle to the rotation axis. By assuming the rigid-field limit in which material…
Galactic winds are a crucial player in galaxy formation and evolution, but observations of them have proven extraordinarily difficult to interpret, leaving large uncertainties even in basic quantities such as mass outflow rates. Part of…
We present a simple model that explains the origin of warm diffuse gas seen primarily as highly ionized absorption line systems in the spectra of background sources. We predict the observed column densities of several highly ionized…
Far Ultraviolet Spectroscopic Explorer spectra of 22 Galactic halo stars are studied to determine the amount of O VI in the Galactic halo between ~0.3 and \~10 kpc from the Galactic mid-plane. Strong O VI 1031.93 A absorption was detected…
We present measurements of the OII(3727) emission line width for a complete sample of 24 blue field galaxies (21.25<B<22, B-R<1.2) at <z>=0.25, obtained with the AUTOFIB fibre spectrograph on the Anglo-Australian Telescope. Most emission…
Our view of the high velocity cloud (HVC) system is changing dramatically with new observations from the Far Ultraviolet Spectroscopic Explorer mission and the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. In…