Dynamical and chemical evolution of gas-rich dwarf galaxies

Recchi, Simone; Matteuccí, F.; D’Ercole, A.

doi:10.1046/j.1365-8711.2001.04189.x

Cited by 161 publications

(249 citation statements)

References 67 publications

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“…The assumption of a larger β in low-mass galaxies simply means that these galaxies are able to expel large fractions, relative to their total mass, of newly synthesized metals, but only tiny fractions of pristine ISM, in agreement with many hydrodynamical studies of star-forming dwarf galaxies (e.g. MacLow & Ferrara 1999;D'Ercole & Brighenti 1999;Recchi et al 2001). -We did not explore the case in which the efficiency of star formation increases with galactic mass, since the SFR does not appear in the solutions of the analytical models.…”

Section: Discussionsupporting

confidence: 74%

The origin of the mass-metallicity relation: an analytical approach

Spitoni¹,

Calura

Matteuccí

et al. 2010

A&A

119

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Context. The mass-metallicity (MZ) relation in star-forming galaxies at all redshifts has been recently established. It is therefore important to understand the physical mechanisms underlying such a relation. Aims. We aim at studying some possible physical mechanisms contributing to the MZ relation by adopting analytical solutions of chemical evolution models, including infall and outflow. Methods. Analytical models assume the instantaneous recycling approximation, which is still an acceptable assumption for elements produced on short timescales such as oxygen, which is the measured abundance in the MZ relation.We explore the hypotheses of a variable galactic wind rate, infall rate, and yield per stellar generation (i.e. a variation in the IMF), as possible causes for the MZ relation. Results. By means of analytical models, we computed the expected O abundance for galaxies of a given total baryonic mass and gas mass.The stellar mass was derived observationally and the gas mass was derived by inverting the Kennicutt law of star formation, once its rate is known. Then we tested how the parameters describing the outflow, infall, and IMF should vary to reproduce the MZ relation, and we exclude the cases where such a variation leads to unrealistic situations. Conclusions. We find that a galactic wind rate increasing with decreasing galactic mass or a variable IMF are both viable solutions for the MZ relation. A variable infall rate instead is not acceptable. It is difficult to differentiate among the outflow and IMF solutions by only considering the MZ relation, and other observational constraints should be taken into account in selecting a specific solution. For example, a variable efficiency of star formation increasing with galactic mass can also reproduce the MZ relation and explain the downsizing in star formation suggested for ellipticals. The best solution could be a variable efficiency of star formation coupled with galactic winds, which are indeed observed in low-mass galaxies.

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Section: Discussionsupporting

confidence: 74%

The origin of the mass-metallicity relation: an analytical approach

Spitoni¹,

Calura

Matteuccí

et al. 2010

A&A

119

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“…According to the former explanation, although our models stop the global wind phase, SNe Ia ejecta might be still able to escape the galactic potential well, thus lowering the iron abundance in the ISM (e.g. Recchi et al 2001). In order to preserve the observed L X − L B and L X −T X relations, this could be obtained by e.g.…”

Section: The Chemistry Of the Ismmentioning

confidence: 89%

Massive elliptical galaxies in X-rays: The role of late gas accretion

Pipino

Kawata

Gibson

et al. 2005

A&A

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Abstract. We present a new chemical evolution model meant to be a first step in the self-consistent study of both optical and X-ray properties of elliptical galaxies. Detailed cooling and heating processes in the interstellar medium (ISM) are taken into account using a mono-phase one-zone treatment which allows a more reliable modelling of the galactic wind regime with respect to previous work. The model successfully reproduces simultaneously the mass-metallicity, the colour-magnitude, the L X − L B and the L X − T relations, as well as the observed trend of the [Mg/Fe] ratio as a function of σ, by adopting the prescriptions of Pipino & Matteucci (2004) for the gas infall and star formation timescales. We found that a late secondary accretion of gas from the environment plays a fundamental role in driving the L X − L B and L X − T relations and can explain their large observational scatter. The iron discrepancy, namely the too high predicted iron abundance in X-ray haloes of ellipticals compared to observations, still persists. On the other hand, we predict [O/Fe] in the ISM which is in good agreement with the most recent observations. We suggest possible mechanisms acting on a galactic scale which may solve the iron discrepancy. In particular, mixing of gas driven by AGNs may preserve the gas mass (and thus the X-ray luminosity) while diluting the iron abundance. New predictions for the amounts of iron, oxygen and energy ejected into the intracluster medium (ICM) are presented and we conclude that type Ia supernovae (SNe Ia) play a fundamental role in the ICM enrichment. SNe Ia activity, in fact, may power a galactic wind lasting for a considerable amount of the galactic lifetime, even in the case for which the efficiency of energy transfer into the ISM per SN Ia event is less than unity.

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“…Thornton et al (1998) performed single 1D supernova explosion models and derived SN = 0.1. Estimates from cumulative SNII explosions, forming superbubbles, suggest a significant dependence of SN on the temperature and density of the external medium (Recchi et al 2001;Recchi 2014). A different approach, where the contribution of a whole stellar population is considered (Melioli & de Gouveia Dal Pino 2004) clearly shows that SN is a function of time.…”

Section: Discussion and Model Caveatsmentioning

confidence: 99%

“…We derive the rates of Type Ia supernovae following the ideas and notations laid out in Matteucci & Recchi (2001). The number of binary systems (per unit mass of the binary system M B ) that are capable of producing a SNIa explosion can be calculated as…”

Section: Supernova Type Ia Ratesmentioning

confidence: 99%

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Stellar hydrodynamical modeling of dwarf galaxies: simulation methodology, tests, and first results

Vorobyov

Recchi

Hensler

2015

A&A

Self Cite

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Context. In spite of enormous progress and brilliant achievements in cosmological simulations, they still lack numerical resolution or physical processes to simulate dwarf galaxies in sufficient detail. Accurate numerical simulations of individual dwarf galaxies are thus still in demand. Aims. We aim to improve available numerical techniques to simulate individual dwarf galaxies. In particular, we aim to (i) study in detail the coupling between stars and gas in a galaxy, exploiting the so-called stellar hydrodynamical approach; and (ii) study for the first time the chemodynamical evolution of individual galaxies starting from self-consistently calculated initial gas distributions.Methods. We present a novel chemodynamical code for studying the evolution of individual dwarf galaxies. In this code, the dynamics of gas is computed using the usual hydrodynamics equations, while the dynamics of stars is described by the stellar hydrodynamics approach, which solves for the first three moments of the collisionless Boltzmann equation. The feedback from stellar winds and dying stars is followed in detail. In particular, a novel and detailed approach has been developed to trace the aging of various stellar populations, which facilitates an accurate calculation of the stellar feedback depending on the stellar age. The code has been accurately benchmarked, allowing us to provide a recipe for improving the code performance on the Sedov test problem. Results. We build initial equilibrium models of dwarf galaxies that take gas self-gravity into account and present different levels of rotational support. Models with high rotational support (and hence high degrees of flattening) develop prominent bipolar outflows; a newly-born stellar population in these models is preferentially concentrated to the galactic midplane. Models with little rotational support blow away a large fraction of the gas and the resulting stellar distribution is extended and diffuse. Models that start from non-self-gravitating initial equilibrium configurations, evolve at a much slower pace owing to lower initial gas density and hence lower star formation rates. The stellar dynamics turns out to be a crucial aspect of galaxy evolution. If we artificially suppress stellar dynamics, supernova explosions occur in a medium that is heated and diluted by previous activity of stellar winds, thus artificially enhancing stellar feedback. Conclusions. The stellar hydrodynamics approach presents a promising tool for numerically studying the coupled evolution of gas and stars in dwarf galaxies.

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Dynamical and chemical evolution of gas-rich dwarf galaxies

Cited by 161 publications

References 67 publications

The origin of the mass-metallicity relation: an analytical approach

The origin of the mass-metallicity relation: an analytical approach

Massive elliptical galaxies in X-rays: The role of late gas accretion

Stellar hydrodynamical modeling of dwarf galaxies: simulation methodology, tests, and first results

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