A high-resolution stellar library for evolutionary population synthesis (original) (raw)
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Stellar Tools for High Resolution Population Synthesis
Revista Mexicana De Astronomia Y Astrofisica, 2005
Presentamos los resultados preliminares de la aplicación de una nueva biblioteca estelar de espectros sintéticos de alta resolución (con base en los códigos ATLAS9 y SYNTHE desarrollados por Kurucz) para el cálculo de la distribución de energía espectral en el ultravioleta-óptico de poblaciones estelares simples (SSPs). Para este propósito, la biblioteca se acopló con el código de síntesis de poblaciones de Buzzoni. Una parte de este artículo está dedicada a ilustrar de manera cuantitativa el grado al cual las bibliotecas estelares sintéticas representan a las estrellas reales.
Evolutionary stellar population synthesis at high spectral resolution: optical wavelengths
Monthly Notices of the Royal Astronomical Society, 2005
We present the single stellar population (SSP) synthesis results of our new synthetic stellar atmosphere models library with a spectral sampling of 0.3Å, covering the wavelength range from 3000Å to 7000Å for a wide range of metallicities (twice solar, solar, half solar and 1/10 solar). The stellar library is composed of 1650 spectra computed with the latest improvements in stellar atmospheres. In particular, it incorporates non-LTE line-blanketed models for hot (T eff 27500 K), and LTE lineblanketed models (Phoenix) for cool (3000 T eff 4500 K) stars. Because of the high spectral resolution of this library, evolutionary synthesis models can be used to predict the strength of numerous weak absorption lines and the evolution of the profiles of the strongest lines over a wide range of ages. The SSP results have been calculated for ages 1 Myr to 17 Gyr using the stellar evolutionary tracks provided by the Geneva and Padova groups. For young stellar populations, our results have a very detailed coverage of high-temperature stars with similar results for the Padova and Geneva isochrones. For intermediate and old stellar populations, our results, once degraded to a lower resolution, are similar to the ones obtained by other groups (limitations imposed by the stellar evolutionary physics notwidthstanding). The limitations and advantages of our models for the analysis of integrated populations are described. The full set of the stellar library and the evolutionary models are available for retrieval at the websites http://www.iaa.csic.es/∼rosa and http://www.iaa.csic.es/∼mcs/Sed@, or on request from the first two authors.
Monthly Notices of The Royal Astronomical Society, 2010
We present synthetic spectral energy distributions (SEDs) for single-age, singlemetallicity stellar populations (SSPs) covering the full optical spectral range at moderately high resolution (FWHM=2.3Å). These SEDs constitute our base models, as they combine scaled-solar isochrones with a empirical stellar spectral library (MILES), which follows the chemical evolution pattern of the solar neighbourhood. The models rely as much as possible on empirical ingredients, not just on the stellar spectra, but also on extensive photometric libraries, which are used to determine the transforma-
POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations
2022
Most massive stars are members of a binary or a higher-order stellar systems, where the presence of a binary companion can decisively alter their evolution via binary interactions. Interacting binaries are also important astrophysical laboratories for the study of compact objects. Binary population synthesis studies have been used extensively over the last two decades to interpret observations of compact-object binaries and to decipher the physical processes that lead to their formation. Here, we present POSYDON, a novel, binary population synthesis code that incorporates full stellar-structure and binary-evolution modeling, using the MESA code, throughout the whole evolution of the binaries. The use of POSYDON enables the self-consistent treatment of physical processes in stellar and binary evolution, including: realistic mass-transfer calculations and assessment of stability, internal angular-momentum transport and tides, stellar core sizes, mass-transfer rates and orbital periods...
The Astronomical Journal, 2007
Stellar evolution tracks and isochrones are key inputs for a wide range of astrophysical studies; in particular, they are essential to the interpretation of photometric and spectroscopic observations of resolved and unresolved stellar populations. We have made available to the astrophysical community a large, homogenous database of up-to-date stellar tracks and isochrones, and a set of programs useful in population synthesis studies. In this paper we first summarize the main properties of our stellar model database (BaSTI) already introduced in Pietrinferni et al. (2004) and Pietrinferni et al. (2006). We then discuss an important update of the database, i.e., the extension of all stellar models and isochrones until the end of the thermal pulses along the Asymptotic Giant Branch. This extension of the library is particularly relevant for stellar population analyses in the near-infrared, or longer wavelengths, where the contribution to the integrated photometric properties by cool and bright Asymptotic Giant Branch stars is significant. A few comparisons with empirical data are also presentend and briefly discussed. We then present three web-tools that allow an interactive access to the database, and make possible to compute user-specified evolutionary tracks, isochrones, stellar luminosity functions, plus synthetic Color-Magnitude-Diagrams and integrated magnitudes for arbitrary Star Formation Histories. All these web tools are available at the BaSTI database official site: http://www.oa-teramo.inaf.it/BASTI.
Validation of optimized population synthesis through mock spectra and Galactic globular clusters
Optimized population synthesis provides an empirical method to extract the relative mix of stellar evolutionary stages and the distribution of atmospheric parameters within unresolved stellar systems, yet a robust validation of this method is still lacking. We here provide a calibration of population synthesis via non-linear bound-constrained optimization of stellar populations based upon optical spectra of mock stellar systems and observed Galactic globular clusters (GGCs). The MILES stellar library is used as a basis for mock spectra as well as templates for the synthesis of deep GGC spectra from Schiavon et al. Optimized population synthesis applied to mock spectra recovers mean light-weighted stellar atmospheric parameters within a mean uncertainty of 240 K, 0.04 dex, and 0.03 dex for Teff, log g, and [Fe/H], respectively. We use additional information from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) deep colour-magnitude diagrams (CMDs) from Sarajedini et al. and literature metallicities to validate our optimization results on GGCs. Decompositions of both mock and GGC spectra confirm the method's ability to recover the expected mean light-weighted metallicity in dust-free conditions (E(B - V) ≲ 0.15) with uncertainties comparable to evolutionary population synthesis methods. Dustier conditions require either appropriate dust modelling when fitting to the full spectrum, or fitting only to select spectral features. We derive light-weighted fractions of stellar evolutionary stages from our population synthesis fits to GGCs, yielding on average a combined 25 ± 6 per cent from main-sequence and turn-off dwarfs, 64 ± 7 per cent from subgiant, red giant, and asymptotic giant branch stars, and 15 ± 7 per cent from horizontal branch stars and blue stragglers. Excellent agreement is found between these fractions and those estimated from deep HST/ACS CMDs. Overall, optimized population synthesis remains a powerful tool for understanding the stellar populations within the integrated light of galaxies and globular clusters.
SPECTRAL: A new evolutionary synthesis code. Application to the irregular Galaxy NGC 1560
Astronomy & Astrophysics, 2003
We have developed a new evolutionary synthesis code, which incorporates the output from chemical evolution models. We compare results of this new code with other published codes, and we apply it to the irregular galaxy NGC 1560 using sophisticated chemical evolution models. The code makes important contributions in two areas: a) the generation of synthetic populations with time-dependent star formation rates and stellar populations of different metallicities; b) the extension of the set of stellar tracks from the Geneva group by adding the AGB phases for m i /M ≥ 0.8, as well as the low mass stars. Our code predicts spectra, broad band colors, and Lick indices by using a spectral library, covering a more complete grid of stellar parameters than previous models. The application of the code to the galaxy NGC 1560 constrains the star formation age of its stellar population at around 10.0 Gyr.
A new, efficient stellar evolution code for calculating complete evolutionary tracks
Monthly Notices of the Royal Astronomical Society, 2009
We present a new stellar evolution code and a set of results, demonstrating its capability at calculating full evolutionary tracks for a wide range of masses and metallicities. The code is fast and efficient, and is capable of following through all evolutionary phases, without interruption or human intervention.
Towards multiple-star population synthesis
Monthly Notices of the Royal Astronomical Society, 2009
The multiplicities of stars, and some other properties, were collected recently by Eggleton & Tokovinin, for the set of 4559 stars with Hipparcos magnitude brighter than 6.0 (4558 excluding the Sun). In this paper I give a numerical recipe for constructing, by a Monte Carlo technique, a theoretical ensemble of multiple stars that resembles the observed sample. Only multiplicities up to eight are allowed; the observed set contains only multiplicities up to seven. In addition, recipes are suggested for dealing with the selection effects and observational uncertainties that attend the determination of multiplicity. These recipes imply, for example, that to achieve the observed average multiplicity of 1.53, it would be necessary to suppose that the real population has an average multiplicity slightly over 2.0. This numerical model may be useful for (i) comparison with the results of star and star cluster formation theory, (ii) population synthesis that does not ignore multiplicity above 2 and (iii) initial conditions for dynamical cluster simulations.
Rapid stellar and binary population synthesis with COMPAS
2021
COMPAS (Compact Object Mergers: Population Astrophysics and Statistics) is a public rapid binary population synthesis code. COMPAS generates populations of isolated stellar binaries under a set of parametrised assumptions in order to allow comparisons against observational data sets, such as those coming from gravitational-wave observations of merging compact remnants. It includes a number of tools for population processing in addition to the core binary evolution components. COMPAS is publicly available via the github repository https://github.com/TeamCOMPAS/COMPAS/, and is designed to allow for flexible modifications as evolutionary models improve. This paper describes the methodology and implementation of COMPAS. It is a living document which will be updated as new features are added to COMPAS; the current document describes COMPAS v02.21.00.