相关论文: Synthetic spectra for O and B type subdwarf stars
We present chemical composition and fundamental parameters (the effective temperature, surface gravity and radius) for four sharp-lined A-type stars ${\gamma}$ Gem (HD 41705), o Peg (HD 214994), ${\theta}$ Vir (HD 114330) and ${\nu}$ Cap…
We present a library of high-resolution (R $\equiv$ $\lambda$/$\Delta$$\lambda$ $\sim$ 45,000) and high signal-to-noise ratio (S/N $\geq$ 200) near-infrared spectra for stars of a wide range of spectral types and luminosity classes. The…
Spectral synthesis is basically the decomposition of an observed spectrum in terms of the superposition of a base of simple stellar populations of various ages and metallicities, producing as output the star formation and chemical histories…
In view of the importance of accurate fundamental stellar parameters for `Spectro-photometric dating of stars and galaxies", we present simultaneous effective temperature and metallicity determinations for a sample of 40 stars from…
We present the results of a detailed UV and optical spectral analysis of the properties of 6 dwarf O-type stars in the SMC H II region NGC 346. Stellar parameters, chemical abundances, and wind parameters have been determined using NLTE…
The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering…
The plethora of spectra of OB-type stars in observatory archives and the much larger numbers to come from the WEAVE and 4MOST spectroscopic facilities require efficient, but also accurate and precise methods for (semi)automatic quantitative…
(abridged) We studied a large sample of ~14000 dwarf star-forming galaxies with strong emission lines selected from the Sloan Digital Sky Survey (SDSS) and distributed in the redshift range of z~0-0.6. We modelled spectral energy…
Neutral sodium is an important tracer of the Galactic chemical evolution, a powerful diagnostic of different stellar populations, and the subject of detailed studies of exoplanet atmospheres via transmission spectroscopy. This work aims to…
The atmospheres of massive O-type stars (O stars) are dynamic, turbulent environments resulting from radiatively driven instabilities over the iron bump, located slightly beneath the stellar surface. Here, complex radiation hydrodynamic…
We present an update of our low-resolution spectroscopic follow-up and model atmosphere analysis of hot subdwarf stars from the Galaxy Evolution Explorer (GALEX) survey. Targets were selected on the basis of colour indices calculated from…
In order to complete Stark broadening data for Ne II, and O III lines, needed for analysis of stellar atmospheres, we determined, within the semiclassical perturbation method, the missing Stark broadening parameters for the broadening by…
Based on an exteded grid of NLTE, line blanketed model atmospheres with stellar winds as calculated by means of FASTWIND, we have investigated the change in the strengths of strategic Helium transitions in the optical as caused by a 0.3…
Spectral analysis needs the observation of lines of successive ionization stages in order to evaluate the ionization equilibrium (of a particular species) which is a sensitive indicator for the effective temperature. Since stars with…
Stellar abundances, coupled with kinematics are a unique way to understand the chemo-dynamical processes that occurred to build the Milky Way and its local volume as we observe today. However, measuring abundances is challenging as one…
We present initial results from a program aimed at establishing a network of hot DA white dwarfs to serve as spectrophotometric standards for present and future wide-field surveys. These stars span the equatorial zone and are faint enough…
We present a comparison of low-resolution spectra of 60 stars covering the whole M-dwarf sequence. Using the most recent PHOENIX BT-Settl stellar model atmospheres (see paper by F. Allard, in this book) we do a first quantitative compari-…
As part of a project to model the integrated spectra and colors of elliptical galaxies through evolutionary synthesis, we have refined our synthetic spectrum calculations of M giants. After critically assessing three effective temperature…
Using a Hartree-Fock formalism, we estimate energy levels and photon cross sections for atomic iron in magnetic fields B ~ 10^13 G. Computing ionization equilibrium and normal mode opacities with these data, we construct LTE neutron star…
The current and forthcoming observations of large samples of high-redshift galaxies selected according to various photometric and spectroscopic criteria can be interpreted in the context of galaxy formation, by means of models of evolving…