Related papers: Ensemble age inversions for large spectroscopic su…
We present a novel statistical algorithm, Stellar Ages, which currently infers the age, metallicity, and extinction posterior distributions of stellar populations from their magnitudes. While this paper focuses on these parameters, the…
Estimating age distributions, or star formation histories, of stellar populations in the Milky Way is important in order to study the evolution of trends in elemental abundances and kinematics. We build on previous work to develop an…
Context. Determining stellar characteristics such as the radius, the mass or the age is crucial when studying stellar evolution, exoplanetary systems or characterising stellar populations in the Galaxy. Asteroseismology is the golden path…
Constraints on the formation and evolution of the Milky Way Galaxy require multi-dimensional measurements of kinematics, abundances, and ages for a large population of stars. Ages for luminous giants, which can be seen to large distances,…
Current instruments and spectral analysis programs are now able to decompose the integrated spectrum of a stellar system into distributions of ages and metallicities. The reliability of these methods have rarely been tested on nearby…
Over the last few years, many studies have found an empirical relationship between the abundance of a star and its age. Here we estimate spectroscopic stellar ages for 178 825 red-giant stars observed by the APOGEE survey with a median…
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…
Stellar ages are key for determining the formation history of the Milky Way, but are difficult to measure precisely. Furthermore, methods that use chemical abundances to infer ages may entangle the intrinsic evolution of stars with the…
Context. Stellar ages are typically very difficult to estimate for field stars. New empirical methods, based on abundance ratios of chemical elements, are emerging and need to be calibrated. Aims. Our main aim is to contribute to revealing…
In this third paper of a series on the precision of obtaining ages of stellar populations using the full spectrum fitting technique, we examine the precision of this technique in deriving possible age spreads within a star cluster. We test…
We present a new method of quantifying a galaxy's accretion history from its integrated spectrum alone. Using full spectral fitting and calibrated regularization techniques we show how we can accurately derive a galaxy's mass distribution…
Using a novel approach we have reanalized the question of whether the extreme star forming galaxies known as HII galaxies are truly young or rejuvenated old systems. We first present a method of inversion that applies to any monotonic…
Globular cluster ages provide both an important test of models of globular cluster formation and a powerful method to constrain the assembly history of galaxies. Unfortunately, measuring the ages of unresolved old stellar populations has…
We present inversion techniques aiming at recovering the stellar content (age, metallicity, extinction) and kinematics of a stellar population from its absorption line spectrum. These techniques use new synthetic high resolution spectra…
Large scale surveys open the possibility to investigate Galactic evolution both chemically and kinematically, however, reliable stellar ages remain a major challenge. Detailed chemical information provided by high-resolution spectroscopic…
Star clusters are studied widely both as benchmarks for stellar evolution models and in their own right. Cluster age and mass distributions within galaxies are probes of star formation histories, and of cluster formation and disruption…
The upcoming new generation of optical spectrographs on four-meter-class telescopes will provide invaluable information for reconstructing the history of star formation in individual galaxies up to redshifts of about 0.7. We aim at defining…
A deep understanding of the Milky Way galaxy, its formation and evolution requires observations of huge numbers of stars. Stellar photometry, therefore, provides an economical method to obtain intrinsic stellar parameters. With the addition…
In the coming years, detailed chemical abundances from large-scale high-resolution spectroscopic surveys will become available for vast numbers of stars across the Milky Way. Previous work has suggested that abundance ratios from these…
The measurement of the structure of stellar populations in the Milky Way disk places fundamental constraints on models of galaxy formation and evolution. Previously, the disk's structure has been studied in terms of populations defined…