Related papers: FASTAR -- I. Continuous and differentiable evoluti…
Modern large-scale photometric surveys have provided us with multi-band photometries of billions of stars. Determining the stellar atmospheric parameters, such as the effective temperature (\teff) and metallicities (\feh), absolute…
Characterizing the fundamental parameters of stars from observations is crucial for studying the stars themselves, their planets, and the galaxy as a whole. Stellar evolution theory predicting the properties of stars as a function of…
Any stellar system with a star formation history (SFH) more extended than a massive star's lifetime will be composite in metallicity. Our method of chemically consistent evolutionary synthesis tries to account for the increasing initial…
Low-mass stars (M<0.4Msun) are thought to comprise the bulk of the stellar mass of galaxies but they constitute only of order a percent of the bolometric luminosity of an old stellar population. Directly estimating the number of low-mass…
Around the turn of the last century, star clusters of all kinds were considered "simple" stellar populations. Over the past decade, this situation has changed dramatically. At the same time, star clusters are among the brightest stellar…
The termination in the white dwarf luminosity function is a standard diagnostic tool for measuring the total age of nearby stellar populations. In this paper, an algorithm is presented for inverting the full white dwarf luminosity function…
We show that different stellar-mass estimation methods yield overall mass scales that disagree by factors up to ~2 for the z=0 galaxy population, and more importantly, relative mass scales that sometimes disagree by factors >~3 between…
We derive new spectral H_gamma index definitions which are robust age indicators for old and relatively old stellar populations and thus have great potential for solving the age-metallicity degeneracy of galaxy spectra. To study H_gamma as…
We present Gemini/GNIRS cross-dispersed near-infrared spectra of 12 nearby early-type galaxies, with the aim of testing commonly used stellar population synthesis models. We select a subset of galaxies from the atlas/ sample which span a…
Does the IMF vary? Is it significantly different in metal-rich environments than in metal-poor ones? Theoretical work predicts this to be the case. But in order to provide robust empirical evidence for this, the researcher must understand…
The stellar initial mass function (IMF) is among the most fundamental distributions in astrophysics, defined as the mass spectrum of stars produced in a single star-formation event. Even in the solar neighbourhood, where measurements can be…
The stellar initial mas function (IMF) has been described as being invariant, bottom heavy or top-heavy in extremely dense star burst conditions. To provide usable observable diagnostic we calculate redshift dependent spectral energy…
We present a comparative test of four widely used full spectral fitting codes, with the aim of answering the question: how robust is the retrieval of the stellar initial mass function (IMF) and other stellar properties of galaxies? We used…
We present realistic models for massive Population III stars and stellar populations based on non-LTE model atmospheres, recent stellar evolution tracks and up-to-date evolutionary synthesis models, to study their spectral properties,…
Stellar population synthesis (SPS) models are a key tool for deriving the age, metallicity, radial velocity and reddening of star clusters from their integrated spectra. Using a sample of 129 star clusters with high-quality spectra, we…
Stellar population synthesis models are an essential tool with which galaxy physical parameters are extracted from observations. However they are built on assumptions designed for use in the local Universe, and not always appropriate to…
Three basic ingredients are required to generate a simple stellar population (SSP) library, i.e., an initial mass function (IMF), a stellar evolution model/isochrones, and an empirical/theoretical stellar spectral library. However, there…
(Abridged) In a recent work we explored the dependence of galaxy stellar population properties derived from broad-band spectral energy distribution fitting on the fitting parameters, e.g. SFHs, age grid, metallicity, IMF, dust reddening,…
The advent of space-based observatories such as CoRoT and Kepler has enabled the testing of our understanding of stellar evolution on thousands of stars. Evolutionary models typically require five input parameters, the mass, initial Helium…
Galactic binaries are expected to be the most numerous LISA sources and to produce a stochastic gravitational-wave foreground whose spectral shape encodes information about the underlying population. Extracting this information with…