Related papers: Modeling Emission-Line Surface Brightness in a Mul…
Outflows are a key part of the galactic gas cycle and crucial in shaping the star formation activity in their host galaxy. Yet, in simulations of galaxy evolution, modeling these outflows in their multi-phase nature and over the relevant…
We present strong constraints on the spacetime variation of the fine-structure constant $\alpha$ using the Dark Energy Spectroscopic Instrument (DESI). In this pilot work, we utilize $\sim110,000$ galaxies with strong and narrow O III…
Equations of cosmic dynamics for a model of the opaque Universe are derived and tested on supernovae (SNe) Ia observations. The model predicts a cyclic expansion/contraction evolution of the Universe within a limited range of scale factors.…
High signal-to-noise, representative spectra of star-forming galaxies at z~2, obtained via stacking, reveal a high-velocity component underneath the narrow H-alpha and [NII] emission lines. When modeled as a single Gaussian, this broad…
We have investigated the stellar and wind properties of a sample of five late-type O dwarfs in order to address the weak wind problem. A grid of TLUSTY models was used to obtain the stellar parameters, and the wind parameters were…
Galactic superwinds may be driven by very hot outflows generated by overlapping supernovae within the host galaxy. We use the Chevalier & Clegg (CC85) wind model and the observed correlation between X-ray luminosities of galaxies and their…
We report new HST COS and STIS spectroscopy of a star-forming region (~100 solar masses/year) in the center of the X-ray cluster RXJ1532.9+3021 (z=0.362), to follow-up the CLASH team discovery of luminous UV filaments and knots in the…
We explore the origin of the observed Lya and other UV lines from galaxies at z<3.7 by detailed modelling of the spectra. The objects are chosen among those showing a) UV-optical-near-IR lines, b) only UV lines and c) those showing Lya in…
We present a versatile family of model galactic outflows including non-uniform mass and energy source distributions, a gravitational potential from an extended mass source, and radiative losses. The model easily produces steady-state wind…
We derive projected rotational velocities (vsini) for a sample of 156 Galactic OB star members of 35 clusters, HII regions, and associations. The HeI lines at $\lambda\lambda$4026, 4388, and 4471A were analyzed in order to define a…
We present quantitative studies of 8 late O and early B-type supergiants in the Magellanic Clouds using far-ultraviolet FUSE, ultraviolet IUE/HST and optical VLT-UVES spectroscopy. Temperatures, mass-loss rates and CNO abundances are…
We investigate the rest-frame Ultraviolet (UV, $\lambda\sim2000$\AA) surface brightness (SB) evolution of galaxies up to $z\sim6$ using a variety of deep Hubble Space Telescope imaging. UV SB is a measure of the density of emission from…
Context. Mass-loss, occurring through radiation driven supersonic winds, is a key issue throughout the evolution of massive stars. Two outstanding problems are currently challenging the theory of radiation-driven winds: wind clumping and…
Opacity is a property of many plasmas, and it is normally expected that if an emission line in a plasma becomes optically thick, its intensity ratio to that of another transition that remains optically thin should decrease. However,…
The intense star formation in starburst galaxies results in the formation of intense winds that sweep matter up to several kpc out of the galactic plane. These winds can be detected in many bands of the electromagnetic spectrum. In this…
We use high-resolution cosmological hydrodynamical AMR simulations to predict the characteristics of La emission from the cold gas streams that fed galaxies in massive haloes at high redshift. The La luminosity in our simulations is powered…
We present a simple, differentiable method for predicting emission line strengths from rest-frame optical continua using an empirically-determined mapping. Extensive work has been done to develop mock galaxy catalogues that include robust…
Chandra high energy resolution observations have now been obtained from numerous non-peculiar O and early B stars. The observed X-ray emission line properties differ from pre-launch predictions, and the interpretations are still…
Using $HST$/COS observations of the twin quasar lines of sight Q$0107-025$A $\&$ Q$0107-025$B, we report on the physical properties, chemical abundances and transverse sizes of gas in a multiple galaxy environment at $z = 0.399$ across a…
(Abridged) We provide empirical constraints on the different physical components that can act to yield temporal variability in predominantly or partially wind-formed optical lines of luminous OB stars, and thus potentially affect the…