Models for Massive Stellar Populations with Rotation

Vázquez, Gerardo A.; Leitherer, Claus; Schaerer, D.; Meynet, Georges; Maeder, A.

doi:10.1086/518589

Cited by 68 publications

(86 citation statements)

References 53 publications

(116 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…sensitive to input physics such as the treatment of rotation (Vázquez et al 2007), to the treatment of advanced phases such as TP-AGB stars (Maraston et al 2006, cf. ) and others.…”

Section: Discussionmentioning

confidence: 99%

The impact of nebular emission on the ages of z${\sf \approx}$ 6 galaxies

Schaerer¹,

Barros²

2009

A&A

291

345

View full text Add to dashboard Cite

Aims. We examine the influence of nebular continuous and line emission in high redshift star forming galaxies on determinations of their age, formation redshift and other properties from SED fits. Methods. We include nebular emission consistently with the stellar emission in our SED fitting tool and analyse differentially a sample of 10 z ≈ 6 galaxies in the GOODS-S field studied earlier by Eyles et al. (2007). Results. We find that the apparent Balmer/4000 Å breaks observed in a number of z ≈ 6 galaxies detected at > ∼ 3.6 µm with IRAC/Spitzer can be mimicked by the presence of strong restframe optical emission lines, implying in particular younger ages than previously thought. Applying these models to the small sample of z ≈ 6 galaxies, we find that this effect may lead to a typical downward revision of their stellar ages by a factor ∼ 3. In consequence their average formation redshift may drastically be reduced, and these objects may not have contributed to cosmic reionisation at z > 6. Extinction and stellar mass estimates may also be somewhat modified, but to a lesser extent. Conclusions. Careful SED fits including nebular emission and treating properly uncertainties and degeneracies are necessary for more accurate determinations of the physical parameters of high-z galaxies.

show abstract

“…sensitive to input physics such as the treatment of rotation (Vázquez et al 2007), to the treatment of advanced phases such as TP-AGB stars (Maraston et al 2006, cf. ) and others.…”

Section: Discussionmentioning

confidence: 99%

The impact of nebular emission on the ages of z${\sf \approx}$ 6 galaxies

Schaerer¹,

Barros²

2009

A&A

291

345

View full text Add to dashboard Cite

show abstract

“…However, we note that the comparison of models with observations and the discussion about whether the rotating models reproduce the observed properties of massive stars better than non-rotating models is currently a subject of debate (e.g. Hamann et al 2006;Meynet & Maeder 2005;Eldridge & Vink 2006;Vazquez & Leitherer 2007).…”

Section: Stellar Evolutionmentioning

confidence: 99%

Using population synthesis of massive stars to study the interstellar medium near OB associations

Voss

Diehl²,

Hartmann

et al. 2009

A&A

127

View full text Add to dashboard Cite

Aims. We study the massive stars in OB associations and their surrounding interstellar medium environment, using a population synthesis code. Methods. We developed a new population synthesis code for groups of massive stars, where we model the emission of different forms of energy and matter from the stars of the association. In particular, the ejection of the two radioactive isotopes 26 Al and 60 Fe is followed, as well as the emission of hydrogen ionizing photons, and the kinetic energy of the stellar winds and supernova explosions. We investigate various alternative astrophysical inputs and the resulting output sensitivities, especially effects due to the inclusion of rotation in stellar models. As the aim of the code is the application to relatively small populations of massive stars, special care is taken to address their statistical properties. Our code incorporates both analytical statistical methods applicable to small populations, as well as extensive Monte Carlo simulations. Results. We find that the inclusion of rotation in the stellar models has a large impact on the interactions between OB associations and their surrounding interstellar medium. The emission of 26 Al in the stellar winds is strongly enhanced, compared to non-rotating models with the same mass-loss prescription. This compensates the recent reductions in the estimates of mass-loss rates of massive stars due to the effects of clumping. Despite the lower mass-loss rates, the power of the winds is actually enhanced for rotating stellar models. The supernova power (kinetic energy of their ejecta) is decreased due to longer lifetimes of rotating stars, and therefore the wind power dominates over supernova power for the first 6 Myr after a burst of star-formation. For populations typical of nearby star-forming regions, the statistical uncertainties are large and clearly non-Gaussian.

show abstract

“…However the physical mechanisms which affect mass loss and its dependence on metallicity are not still completely understood and thus the range of possible efficiencies for the phenomenon is very wide (see e.g. the discussion in Vázquez et al 2005). In this paper we work in the canonical regime, also because we concentrate on intermediate mass stars but to take into account a possible mass loss contribution, in Sect.…”

Section: Modeling the Blue Loop Morphologymentioning

confidence: 99%

Uncertainties on the theoretical predictions for classical Cepheid pulsational quantities

Valle

Marconi²,

Degl’Innocenti

et al. 2009

A&A

View full text Add to dashboard Cite

Context. With their period-luminosity relation, "classical Cepheids" (CC) are the most common primary distance indicators within the Local Group, also providing an absolute calibration of important secondary distance indicators. However, the predicted position of these pulsators in the HR diagram, along the so called blue loop, that is the expected distribution of Cepheids within the instability strip is affected by several model inputs, reflecting upon the predicted PL relation. Aims. The aim of this work is to quantitatively evaluate the effects on the theoretical PL relation of current uncertainties on the chemical abundances of Cepheids in the Large Magellanic Cloud (LMC) and on several physical assumptions adopted in the evolutionary models. We will separately analyse how the different factors influence the evolutionary and pulsational observables and the resulting PL relation. Methods. To achieve this goal we computed new sets of updated evolutionary and pulsational models. Results. As a result, we find that present uncertainties on the most relevant H and He burning reaction rates do not influence in a relevant way the loop extension in temperature. On the contrary, current uncertainties on the LMC chemical composition significantly affect the loop extension and also reflect in the morphology of the instability strip; however their influence on the predicted pulsational parameters is negligible. We also discussed how overshooting and mass loss, sometimes suggested as possible solutions for the long-standing problem of the Cepheid mass discrepancy, influence the ML relation and the pulsational parameters. Conclusions. In summary, the present uncertainties on the physical inputs adopted in the evolutionary codes and in the LMC chemical composition are negligible for the prediction of the main pulsational properties. On the other hand, the inclusion of overshooting in the previous hydrogen burning phase and/or of mass loss is expected to significantly change the resulting theoretical pulsational scenario for Cepheids, as well as the calibration of their distance scale. These systematic effects are expected to influence the theoretical Cepheid calibration of the secondary distance indicators and in turn the resulting evaluation of the Hubble constant.

show abstract

Models for Massive Stellar Populations with Rotation

Cited by 68 publications

References 53 publications

The impact of nebular emission on the ages of z${\sf \approx}$ 6 galaxies

The impact of nebular emission on the ages of z${\sf \approx}$ 6 galaxies

Using population synthesis of massive stars to study the interstellar medium near OB associations

Uncertainties on the theoretical predictions for classical Cepheid pulsational quantities

Contact Info

Product

Resources

About