A standard stellar library for evolutionary synthesis

Lejeune, T.; Cuisinier, F.; Buser, R.

doi:10.1051/aas:1998405

Cited by 582 publications

(709 citation statements)

References 26 publications

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“…We do this in two steps: first we associate to each star a low-resolution spectrum, covering a broad-wavelength, using the GALEV evolutionary synthesis model (Kotulla et al 2009). GALEV is based on the BaSeL library of model atmospheres (Lejeune et al 1997(Lejeune et al , 1998a low resolution high resolution Figure 1. Stellar spectrum associated to a main sequence star with T eff = 5815, m = 0.72 M and l =0.66 L using the GALEV evolutionary synthesis model.…”

Section: From Stellar Parameters To Stellar Spectramentioning

confidence: 99%

Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

Bianchini

Norris

Ven

et al. 2015

Mon. Not. R. Astron. Soc.

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The detection of intermediate mass black holes in the centres of globular clusters is highly controversial, as complementary observational methods often deliver significantly different results. In order to understand these discrepancies, we develop a procedure to simulate integral field unit (IFU) observations of globular clusters: Simulating IFU Star Cluster Observations (SISCO). The input of our software are realistic dynamical models of globular clusters that are then converted in a spectral data cube. We apply SISCO to Monte Carlo cluster simulations from Downing et al. (2010), with a realistic number of stars and concentrations. Using independent realisations of a given simulation we are able to quantify the stochasticity intrinsic to the problem of observing a partially resolved stellar population with integrated-light spectroscopy. We show that the luminosity-weighted IFU observations can be strongly biased by the presence of a few bright stars that introduce a scatter in the velocity dispersion measurements up to 40% around the expected value, preventing any sound assessment of the central kinematic and a sensible interpretation of the presence/absence of an intermediate mass black hole. Moreover, we illustrate that, in our mock IFU observations, the average kinematic tracer has a mass of 0.75 M , only slightly lower than the mass of the typical stars examined in studies of resolved line-of-sight velocities of giant stars. Finally, in order to recover unbiased kinematic measurements we test different masking techniques that allow us to remove the spaxels dominated by bright stars, bringing the scatter down to a level of only a few percent. The application of SISCO will allow to investigate state-of-the-art simulations as realistic observations.

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Section: From Stellar Parameters To Stellar Spectramentioning

confidence: 99%

Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

Bianchini

Norris

Ven

et al. 2015

Mon. Not. R. Astron. Soc.

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“…Stellar evolution at solar metallicity is modeled with the evolutionary tracks of Bressan et al (1993). The input stellar spectra are based on the library of Lejeune et al (1998), as we are mostly interested in broad band photometry. The SMF is taken from Kroupa (1993), and extends from 0.1 to 120 M .…”

Section: Synthetic Populationsmentioning

confidence: 99%

Accounting for stochastic fluctuations when analysing the integrated light of star clusters

Fouesneau¹,

Lançon²

2010

A&A

111

132

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Context. Star clusters are studied widely both as benchmarks for stellar evolution models and in their own right. Cluster age distributions and mass distributions within galaxies are probes of star formation histories and of cluster formation and disruption processes. The vast majority of clusters in the Universe are small, and it is well known that the integrated fluxes and colours of all but the most massive ones have broad probability distributions, owing to small numbers of bright stars. Aims. This paper goes beyond describing predicted probability distributions to present results of the analysis of cluster energy distributions in an explicitly stochastic context. Methods. The method developed is Bayesian. It provides posterior probability distributions in the age-mass-extinction space, using multi-wavelength photometric observations and a large collection of Monte-Carlo simulations of clusters of finite stellar masses. The main priors are the assumed intrinsic distributions of current mass and current age for clusters in a galaxy. Both UBVI and UBVIK data sets are considered, and the study conducted in this paper is restricted to the solar metallicity. Results. We first use the collection of simulations to reassess and explain errors arising from the use of standard analysis methods, which are based on continuous population synthesis models: systematic errors on ages and random errors on masses are large, while systematic errors on masses tend to be smaller. The age-mass distributions obtained after analysis of a synthetic sample are very similar to those found for real galaxies in the literature. The Bayesian approach, on the other hand, is very successful in recovering the input ages and masses over ages ranging between 20 Myr and 1.5 Gyr, with only limited systematics that we explain. Conclusions. Considering stochasticity is important, more important for instance than the choice of adding or removing near-IR data in many cases. We found no immediately obvious reason to reject priors inspired by previous (standard) analyses of cluster populations in galaxies, i.e., cluster distributions that scale with mass as M −2 and are uniform on a logarithmic age scale.

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“…The spectral evolution of a stellar population is calculated on the basis of the Lejeune et al (1997Lejeune et al ( , 1998 library of model atmosphere spectra for the five metallicities. Luminosities in a wide variety of filter systems and colors are obtained by folding the spectra with the respective filter response functions.…”

Section: Undisturbed Galaxiesmentioning

confidence: 99%

The impact of starbursts and post-starbursts on the photometric evolution of high redshift galaxies

Alvensleben¹,

Bicker

2006

A&A

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We present evolutionary synthesis models for galaxies of spectral types Sa through Sd with starbursts of various strengths triggered at various redshifts and study their photometric evolution before, during, and after their bursts in a cosmological context. We find that bursts at high redshift, even very strong ones, only cause a small blueing of their intrinsically blue young parent galaxies. At lower redshift, in contrast, even small bursts cause a significant blueing of their intrinsically redder galaxies. While the burst phase is generally short, typically a few hundred Myr in normal-mass galaxies, the postburst stage with its red colors and, in particular the very red ones for early bursts at high redshift, lasts much longer, on the order of several Gyr. We find that, even without any dust, which in the postburst stage is not expected to play an important role anyway, models easily reach the colors of EROs in the redshift range z ∼ 2 through z ∼ 0.5 after starbursts at redshifts between 2 and 4. We therefore propose a third alternative for the ERO galaxies beyond the two established ones of passive galaxies vs. dusty starbursts: the dust-free post-(strong-)starbursts. A very first comparison of our models to HDF data with photometric redshifts shows that almost all of the outliers that could not be described with our chemically consistent models for undisturbed normal galaxy types E through Sd can now be explained very well. Galaxies in the redshift range from z ∼ 2.5 to z ∼ 0.5 that are redder, and in some cases much redder, than our reddest undisturbed model for a high-metallicity classical elliptical are well described by post-starburst models after starbursts at redshifts between 2 and 4. Galaxies bluer than our bluest low metallicity Sd model, most of which have redshifts lower than 1, are well explained by ongoing starbursts.

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A standard stellar library for evolutionary synthesis

Cited by 582 publications

References 26 publications

Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations

Accounting for stochastic fluctuations when analysing the integrated light of star clusters

The impact of starbursts and post-starbursts on the photometric evolution of high redshift galaxies

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