A physical mechanism for bursts of star formation

Scalo, J. M.; Struck, Curtis

doi:10.1086/163874

Cited by 130 publications

(162 citation statements)

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“…Romano et al 2005), the IMF and the stellar lifetimes are primarily responsible for uncertanties in the chemical evolution models of the Milky Way. In this work, we assumed that the IMF is constant in space and time and adopted the prescription from Kroupa (1993), instead of the two-slope approximation of Scalo (1986) used by CMR2001. The total surface mass density distribution for the Galactic disk was assumed to be exponential with scale length R D = 3.5 kpc normalized to Σ D (R , t Gal ) = 54 M pc −2 (Romano et al 2000)…”

Section: The Chemical Evolution Modelmentioning

confidence: 99%

“…Table 1 shows the coefficients for the linear equations adopted for τ(R). Figure 1 illustrates the predictions for the dwarf metallicity distribution in the solar neighbourhood (Scalo 1986, represented as a dotted line and Kroupa et al 1993, represented as a dashed line) and the observed corrected values from the Geneva-Copenhagen Survey (GCS) as presented in Holmberg et al (2007). The model predictions using the IMF of Kroupa (1993) provide a closer fit to the wings of the dwarf distribution, especially for higher metallicities and produce fewer metal-poor stars, reducing the well-known "G-dwarf" problem.…”

Section: The Milky Waymentioning

confidence: 99%

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Chemical evolution models for spiral disks: the Milky Way, M 31, and M 33

Marcon-Uchida

Matteuccí

Costa

2010

A&A

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Context. The distribution of chemical abundances and their variation with time are important tools for understanding the chemical evolution of galaxies. In particular, the study of chemical evolution models can improve our understanding of the basic assumptions made when modelling our Galaxy and other spirals. Aims. We test a standard chemical evolution model for spiral disks in the Local Universe and study the influence of a threshold gas density and different efficiencies in the star formation rate (SFR) law on radial gradients of abundance, gas, and SFR. The model is then applied to specific galaxies. Methods. We adopt a one-infall chemical evolution model where the Galactic disk forms inside-out by means of infall of gas, and we test different thresholds and efficiencies in the SFR. The model is scaled to the disk properties of three Local Group galaxies (the Milky Way, M 31 and M 33) by varying its dependence on the star formation efficiency and the timescale for the infall of gas onto the disk. Results. Using this simple model, we are able to reproduce most of the observed constraints available in the literature for the studied galaxies. The radial oxygen abundance gradients and their time evolution are studied in detail. The present day abundance gradients are more sensitive to the threshold than to other parameters, while their temporal evolutions are more dependent on the chosen SFR efficiency. A variable efficiency along the galaxy radius can reproduce the present day gas distribution in the disk of spirals with prominent arms. The steepness in the distribution of stellar surface density differs from massive to lower mass disks, owing to the different star formation histories. Conclusions. The most massive disks seem to have evolved faster (i.e., with more efficient star formation) than the less massive ones, thus suggesting a downsizing in star formation for spirals. The threshold and the efficiency of star formation play a very important role in the chemical evolution of spiral disks. For instance, an efficiency varying with radius can be used to regulate the star formation. The oxygen abundance gradient can steepen or flatten in time depending on the choice of this parameter.

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Section: The Chemical Evolution Modelmentioning

confidence: 99%

Section: The Milky Waymentioning

confidence: 99%

Chemical evolution models for spiral disks: the Milky Way, M 31, and M 33

Marcon-Uchida

Matteuccí

Costa

2010

A&A

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“…Detailed nucleosynthesis from low and intermediate mass stars, type Ia and type II SNe is taken into account. The IMF is taken from Scalo (1986). For details of this model see François et al (2004).…”

Section: The Chemical Evolution Modelsmentioning

confidence: 99%

The evolution of carbon and oxygen in the bulge and disk of the Milky Way

Cescutti¹,

Matteuccí

McWilliam

et al. 2009

A&A

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Context. The evolution of C and O abundances in the Milky Way can impose strong constraints on stellar nucleosynthesis and help in understanding the formation and evolution of our Galaxy. Aims. The aim of this paper is to review the measured C and O abundances in the disk and bulge of the Galaxy and compare the results to predictions of Galactic chemical evolution models. Methods. We adopt two successful chemical evolution models for the bulge and the disk, respectively. They assume the same nucleosynthesis prescriptions but different histories of star formation. Conclusions. We conclude that data and models are consistent with a rapid bulge and thick disk formation timescales, and with metallicity-dependent yields for C and O. The observed too high [C/O] ratios at low metallicity in the bulge may stem from an unaccounted source of carbon: very fast rotating metal poor stars, or metal-poor binary systems whose envelopes were stripped by Roche lobe overflow.

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“…This prediction is a direct consequence of the assumed stellar yields and IMF. The yields of O and Fe from massive stars and the yields of Fe from type Ia SNe are from Nomoto et al (1997), their model W7, while for the IMF we assume that of Scalo (1986 Intuitively, one may think that after a very long time since the end of star formation, when the gas content tends to zero, the abundance ratios will tend to the ratios of their yields per stellar generation (equation 2). This is true, in principle, if the global metal production is considered (namely the metals in stars, and in gas inside and outside galaxies), but it fails if only the metals in the individual components (e.g.…”

Section: Abundance Ratios and Chemical Evolution Of Galaxiesmentioning

confidence: 99%

Interpretation of Abundance Ratios

Matteuccí¹,

Chiappini

2005

Publ. Astron. Soc. Aust

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Abstract:In this paper we discuss abundance ratios and their relation to stellar nucleosynthesis and other parameters of chemical evolution models, reviewing and clarifying the correct use of the observed abundance ratios in several astrophysical contexts. In particular, we start from the well-known fact that abundance ratios depend on stellar yields, initial mass function, and stellar lifetimes, and we show, by means of specific examples, that in some cases it is not correct to infer constraints on the contributions from different supernovae types (Ia, II), and particularly on different sets of yields, in the absence of a complete chemical evolution model taking into account stellar lifetimes. In spite of the fact that some of these results should be well known, we believe that it is useful to discuss the meaning of abundance ratios in the light of several recent claims based upon an incorrect interpretation of observed abundance ratios. In particular, the procedure, often used in the recent literature, of directly deriving conclusions about stellar nucleosynthesis just by relating abundance ratios to yield ratios implicitly assumes the instantaneous recycling approximation. This approximation is clearly not correct when one analyses the contributions of supernovae type Ia relative to supernovae type II as functions of cosmic time. In this paper we show that the uncertainty which arises from adopting this oversimplified procedure in a variety of astrophysical objects, such as elliptical galaxies, the intracluster medium, and high redshift objects, does not allow us to draw any firm conclusion, and that the differences between abundance ratios predicted by models with the instantaneous recycling approximation and models with detailed stellar lifetimes is of the same order as the differences between different sets of yields. On the other hand, if one is interested only in establishing the global metal production (e.g. galaxies plus intracluster medium) over the lifetime of the Universe, then the adoption of simplified arguments can be justified.

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A physical mechanism for bursts of star formation

Cited by 130 publications

References 0 publications

Chemical evolution models for spiral disks: the Milky Way, M 31, and M 33

Chemical evolution models for spiral disks: the Milky Way, M 31, and M 33

The evolution of carbon and oxygen in the bulge and disk of the Milky Way

Interpretation of Abundance Ratios

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