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Francesca Matteucci

Publications and source records attributed to Francesca Matteucci.

At least 19 recordsLinked to original sources
arXiv2026

Chemical Evolution of Galaxies: Past, Present and Future

In this paper I will describe the basic principles of chemical evolution of galaxies, its main ingredients and uncertainties. By means of chemical evolution we can perform the so-called galactic archaeology, which consists in reconstructing the history of star formation of galaxies and in particular of the Milky Way, starting from the observed stellar and gas abundances. Galactic archaeology is a powerful tool to predict also the behaviour of galaxies at high redshift. In particular, we adopt the "time-delay model" which is a way of interpreting the [X/Fe] vs. [Fe/H] relations (X is the abundance of a specific chemical element) in terms of different timescales of the stellar progenitors of the chemical elements relative to Fe, which is the indicator of "metallicity". I will then describe how we can reconstruct the star formation histories of galaxies of different morphological type (spirals, ellipticals) starting from the available observations. Particular attention will be paid to the study of the Milky Way which is the best studied galaxy at the moment. I will start describing the first chemical evolution models and then the most recent ones, the main difference between the old and new models being the observational data to compare with. Finally, I will foresee which could be the future improvements to chemical models and what constraints can we derive to better understand galaxy evolution.

astro-ph.GA↗
arXiv2026

The time-delay model and its applications to galactic archaeology

The time-delay model is the way we interpret the diagram [X/Fe] vs. [Fe/H], where X is the abundance of a generic element from carbon to uranium. This interpretation is based on the lifetimes of stars of different masses producing different elements. The abundance of Fe ([Fe/H]) traces the "stellar metallicity" and is due to supernovae Type Ia, which are believed to be the major producers of Fe, and in part to supernovae core-collapse. In particular, if X is an alpha-element, produced on short timescales from massive stars, the ratio [alpha/Fe] will show an overabundance of the alpha-elements relative to Fe at low metallicity. In fact, the bulk of Fe is produced with a time delay relative to alpha-elements, since Type Ia supernovae are white dwarfs in binary systems and they can have lifetimes as long as the age of the Universe. In this paper, I will show how powerful is the time-delay model in order to interpret the abundance patterns observed in stars and interstellar gas, since it allows us to put constraints on stellar nucleosynthesis as well as on the star formation histories of galaxies. I will present some applications of the time-delay model, in particular to the chemical evolution of the Milky Way and galaxies of different morphological type as well as to the identification of high redshift objects by means of their abundances.

astro-ph.GA↗
arXiv2026

The chemical DNA of the Magellanic Clouds VI. Origin and evolution of neutron-capture elements in the SMC

Context. In the context of galactic archaeology, the study of the Small Magellanic Cloud (SMC) is of crucial importance, as it represents a unique opportunity to study a nearby massive dwarf system. However, theoretical studies of the chemical evolution of this galaxy are strikingly lacking. Aims. In this study, we investigate the chemical enrichment of the SMC galaxy. Besides alpha and Fe-peak elements, we devote particular attention to the evolution of neutron-capture elements with different origin, namely r-process (Eu), weak s-process (Zr) and main s-process (Ba, La). Methods. We develop chemical evolution models that use as input the star formation histories obtained from colour-magnitude diagram fitting. We follow in detail the chemical feedback provided by a large variety of nucleosynthetic sources. Model predictions are compared with recent abundance measurements for the SMC. Results. The developed framework reproduces well all the observables for elements up to the Fe-peak. The abundance patterns of n-capture elements are simultaneously reproduced only by assuming an enhanced contribution from the delayed r-process at low metallicity and a top-lighter IMF relative to the reference IMF by Kroupa (2001). In this way, both the observed very high plateau in [Eu/Fe] and the rising trends in [s-process/Fe] ratios can be reproduced by the models. Conclusions. This study provides for the first time information on the evolution of several n-capture elements in a massive dwarf irregular galaxy, also providing insight on several ingredients driving galactic evolution. Moreover, this work provides a test-bed for further modelling of the SMC in the context of the numerous surveys that will target the Magellanic Clouds in the next years.

astro-ph.GA↗
arXiv2025

Measurement of the $^{35}Cl(n, p)^{35}S$ cross-section at the CERN n\_TOF facility from subthermal energy to 120 keV

Background: The $^{35}Cl(n, p)^{35}S$ reaction is of special interest in three different applications. First, in Boron Neutron Capture Therapy due to the presence of $^{35}Cl$ in brain and skin tissue. Second, it is involved in the creation of $^{36}S$, whose astrophysical origin remains unresolved. Third, in the designing of fast nuclear reactors of new generation based on molten salts. Purpose: To measure the $^{35}Cl(n, p)^{35}S$ cross-section from thermal energy to 120 keV, determine the resonance parameters in this range and Maxwellian Averaged Cross-Section (MACS). Method: We made use of the Time-of-Flight technique with microMEGAS detectors at Experimental Area 2 (EAR-2) of n\_TOF facility at CERN. The $^{10}B(n, \alpha)^{7}Li$ and $^{235}U(n, f)$ reactions were used as references. Rutherford Back-scattering Spectrometry technique was performed at Centro Nacional de Aceleradores (CNA) in Sevilla, in order to accurately determine the masses of the irradiated samples. Results: We obtain a thermal cross-section of $0.470 \pm 0.009$ barns. The $1/v$ energy dependence of the cross-section is observed up to the first resonance at 0.398 keV, the resonances up to 120 keV are analyzed and MACS calculated for $k_{B} T$ from 1 to 100 keV. Conclusions: The $^{35}Cl(n, p)^{35}S$ cross-section has been obtained over a wide energy range for the first time, with high accuracy across the aforementioned range. The thermal cross-section and first two resonances are in agreement with latest evaluation in ENDF/B-VIII.1, while lower resonance strength was found for high energy resonances. These data are used to calculate the MACS for different $k_{B} T$.

nucl-ex↗
arXiv2025

Impact of AGB stars on the chemical evolution of neutron-capture elements

In this paper we discuss the impact of the s-process nucleosynthesis in Asymptotic Giant Branch stars on the enrichment of heavy elements. We review the main steps made on this subject in the last 40 years and discuss the importance of modelling the evolution of the abundances of such elements in our Milky Way. From the comparison between model results and observations, we can impose strong constraints on stellar nucleosynthesis as well as on the evolution of the Milky Way.

astro-ph.GA↗
arXiv2025

Cosmic Threads: Interlinking the Stellar Initial Mass Function from Star-Birth to Galaxies

The stellar initial mass function (sIMF) describes the distribution of stellar masses formed in a single star formation event in a molecular cloud clump. It is fundamental to astrophysics and cosmology, shaping our understanding of unresolved stellar populations, galactic chemical enrichment and habitable zones, and black hole growth. This White Paper reviews studies on the core mass function, stellar multiplicity, and dynamical processes affecting sIMF determinations, as well as the link between star-forming clumps and the galaxy-wide IMF (gIMF). The evidence gleaned from observed systems for the dependency of the sIMF on the metallicity and density of the clump is portrayed. We examine evidence from gravitational lensing, stellar and gas kinematics, and spectral diagnostics to assess environmental dependencies of the gIMF. Theoretical perspectives provide further insights into the sIMF's variability. Beyond summarizing current knowledge, this work aims to establish a shared framework and define strategies for studying a variable IMF in the era of near-infrared integral-field spectroscopy, 30m-class telescopes and major space-based observatories.

astro-ph.GA↗
arXiv2024

Modelling chemical clocks -- Theoretical evidences of the space and time evolution of [s/alpha] in the Galactic disc with Gaia-ESO survey

Chemical clocks based on [s-process elements/alpha-elements] ratios are widely used to estimate ages of Galactic stellar populations. However, the [s/alpha] vs. age relations are not universal, varying with metallicity, location in the Galactic disc, and specific s-process elements. Current Galactic chemical evolution models struggle to reproduce the observed [s/alpha] increase at young ages. We provide chemical evolution models for the Milky Way disc to identify the conditions required to reproduce the observed [s/H], [s/Fe], and [s/alpha] vs. age relations. We adopt a multi-zone chemical evolution model including state-of-the-art nucleosynthesis prescriptions for neutron-capture elements (AGB stars, rotating massive stars, neutron star mergers, magneto-driven supernovae). We explore variations in gas infall, AGB yield dependencies on progenitor stars, and rotational velocity distributions for massive stars. Results are compared with open cluster data from the Gaia-ESO survey. A three-infall scenario for disc formation captures the rise of [s/alpha] with age in the outer regions but fails in the inner ones, especially for second s-process peak elements. Ba production in the last 3 Gyr of chemical evolution would need to increase by half to match observations. S-process contributions from low-mass AGB stars improve predictions but require increases not supported by nucleosynthesis calculations, even with potential i-process contribution. Variations in the metallicity dependence of AGB yields show inconsistent effects across elements. Distributions of massive star rotational velocities fail to improve results due to balanced effects on elements. We confirm that there is no single relationship [s/alpha] vs. age, but that it varies along the MW disc. Current prescriptions for neutron-capture element yields cannot fully capture the complexity of evolution, particularly in the inner disc.

astro-ph.GA↗
arXiv2024

Mapping radial abundance gradients with Gaia-ESO open clusters: Evidence of recent gas accretion in the Milky Way disk

Context. Recent evidences from spectroscopic surveys point towards the presence of a metal-poor, young stellar population in the chemical thin disk. In this context, the investigation of the spatial distribution and time evolution of precise, unbiased abundances is fundamental to disentangle the scenarios of evolution of the Galaxy. Aims. We study the evolution of abundance gradients in the Milky Way by taking advantage of a large sample of open clusters, which are among the best tracers for this purpose. In particular, we use data from the last release of the Gaia-ESO survey. Methods. We perform careful selection of open cluster stars excluding those that may be affected by biases in spectral analysis. The cleaned open clusters sample is compared with detailed chemical evolution models for the Milky Way, using well tested stellar yields and prescription for radial migration. Different scenarios of Galaxy evolution are tested to explain the data, i.e. the two-infall and the three-infall frameworks, suggesting that the chemical thin disk is formed by one or two subsequent gas accretion episodes, respectively. Results. With the performed selection in cluster stars, we still find a metallicity decrease between intermediate age (1<Age/Gyr<3) and young (Age<1Gyr) open clusters. This decrease cannot be explained in the context of the two-infall scenario, even by accounting for the effect of migration and yield prescriptions. The three-infall model, with its late gas accretion in the last 3 Gyr, can explain the low metallic content in young clusters. However, we invoke a milder metal dilution relative to previous findings. Conclusions. To explain the observed low metallic content in young clusters, we propose that a late gas accretion episode triggering metal dilution should have taken place, extending the framework of the three-infall model for the first time to the entire Galactic disk.

astro-ph.GA↗
arXiv2024

Tracing the Milky Way spiral arms with 26Al -- The role of nova systems in the 2D distribution of 26Al

Massive stars are one of the most important and investigated astrophysical production sites of $^{26}$Al, a short-lived radioisotope with $\sim$ 1 Myr half-life. Its short lifetime prevents us from observing its complete chemical history, and only the $^{26}$Al that was recently produced by massive stars can be observed. Hence, it is considered a tracer of star formation rate (SFR). However, important contributions to $^{26}$Al comes from nova systems that pollute the interstellar medium with a large delay, thus partly erasing the correlation between $^{26}$Al and SFR. In this work we describe the 2D distribution of the mass of $^{26}$Al as well as that of massive stars and nova systems in the Milky Way, to investigate their relative contributions to the production of $^{26}$Al. We use a detailed 2D chemical evolution model where the SFR is azimuthally dependent and is required to reproduce the spiral arm pattern observed in the Milky Way. We test two different models, one where the $^{26}$Al comes from massive stars and novae, and one with massive stars only. We then compare the predictions to the $\sim$ 2 M$_{\odot}$ of $^{26}$Al mass observed by the surveys COMPTEL and INTEGRAL. The results show that novae do not trace SFR and, in the solar vicinity, they concentrate in its minima. The effect of novae on the map of the $^{26}$Al mass consists in damping the spiral pattern by a factor of five. Regarding the nucleosynthesis, we find that $\sim$75% of the $^{26}$Al is produced by novae and the $\sim$25% by massive stars. We conclude that novae cannot be neglected as $^{26}$Al producers since the observations can only be reproduced by including their contribution. Moreover, we suggest that bulge novae should eject around six times more material than the disc ones to well reproduce the observed mass of $^{26}$Al.

astro-ph.GA↗
arXiv2024

Neutrino-driven Core-collapse Supernova Yields in Galactic Chemical Evolution

We provide yields from 189 neutrino-driven core-collapse supernova (CCSN) simulations covering zero-age main sequence masses between 11 and 75 solar masses and three different metallicities. Our CCSN simulations have two main advantages compared to previous methods used for applications in Galactic chemical evolution (GCE). Firstly, the mass cut between remnant and ejecta evolves naturally. Secondly, the neutrino luminosities and thus the electron fraction are not modified. Both is key to obtain an accurate nucleosynthesis. We follow the composition with an in-situ nuclear reaction network including the 16 most abundant isotopes and use the yields as input in a GCE model of the Milky Way. We adopt a GCE which takes into account infall of gas as well as nucleosynthesis from a large variety of stellar sources. The GCE model is calibrated to reproduce the main features of the solar vicinity. For the CCSN models, we use different calibrations and propagate the uncertainty. We find a big impact of the CCSN yields on our GCE predictions. We compare the abundance ratios of C, O, Ne, Mg, Si, S, Ar, Ca, Ti, and Cr with respect to Fe to an observational data set as homogeneous as possible. From this, we conclude that at least half of the massive stars have to explode to match the observed abundance ratios. If the explosions are too energetic, the high amount of iron will suppress the abundance ratios. With this, we demonstrate how GCE models can be used to constrain the evolution and deaths of massive stars.

astro-ph.HE↗
arXiv2023

An improved method to measure $\rm ^{12}C/^{13}C$ and $\rm ^{14}N/^{15}N$ abundance ratios: revisiting CN isotopologues in the Galactic outer disk

The variations of elemental abundance and their ratios along the Galactocentric radius result from the chemical evolution of the Milky Way disks. The $\rm ^{12}C/^{13}C$ ratio in particular is often used as a proxy to determine other isotopic ratios, such as $\rm ^{16}O/^{18}O$ and $\rm ^{14}N/^{15}N$. Measurements of $\rm ^{12}CN$ and $\rm ^{13}CN$ (or $\rm C^{15}N$) -- with their optical depths corrected via their hyper-fine structure lines -- have traditionally been exploited to constrain the Galactocentric gradients of the CNO isotopic ratios. Such methods typically make several simplifying assumptions (e.g. a filling factor of unity, the Rayleigh-Jeans approximation, and the neglect of the cosmic microwave background) while adopting a single average gas phase. However, these simplifications introduce significant biases to the measured $\rm ^{12}C/^{13}C$ and $\rm ^{14}N/^{15}N$. We demonstrate that exploiting the optically thin satellite lines of $\rm ^{12}CN$ constitutes a more reliable new method to derive $\rm ^{12}C/^{13}C$ and $\rm ^{14}N/^{15}N$ from CN isotopologues. We apply this satellite-line method to new IRAM 30-m observations of $\rm ^{12}CN$, $\rm ^{13}CN$, and $\rm C^{15}N$ $N=1\to0$ towards 15 metal-poor molecular clouds in the Galactic outer disk ($R_{\rm gc} > $ 12 kpc), supplemented by data from the literature. After updating their Galactocentric distances, we find that $\rm ^{12}C/^{13}C$ and $\rm ^{14}N/^{15}N$ gradients are in good agreement with those derived using independent optically thin molecular tracers, even in regions with the lowest metallicities. We therefore recommend using optically thin tracers for Galactic and extragalactic CNO isotopic measurements, which avoids the biases associated with the traditional method.

astro-ph.GA↗
arXiv2023

Galactic Archaeology with [Mg/Mn] versus [Al/Fe] abundance ratios -- Uncertainties and caveats

The diagram depicting the abundance ratios [Mg/Mn] vs. [Al/Fe] has gained attention in recent literature as a valuable tool for exploring fundamental aspects of the evolution of the Milky Way and the Local Group. In particular, this combination of elements is supposed to be highly sensitive to the star formation history (SFH), unveiled by the imprints left on those abundances. Unfortunately, a complete discussion on the uncertainties associated is still missing, making it difficult to know how reliable the associated results are. In this paper we analyze, by means of detailed chemical evolution models, the nuclear uncertainties of Mg, Al, Mn and Fe to show how different yields can affect the trends in the [Mg/Mn] vs. [Al/Fe] plane. In fact, if different yield assumptions produce conflicting results, then the [Mg/Mn] vs. [Al/Fe] diagram does not represent a strong diagnostic for the SFH of a galaxy. We discuss the results on the [Mg/Mn] vs. [Al/Fe] diagram, as predicted by several Milky Way (MW) and Large Magellanic Cloud (LMC) chemical evolution models adopting different nucleosynthesis prescriptions. The results show that the literature yields require some corrective factors to reproduce the APOGEE DR17 abundances of Mg, Al and Mn in the MW and that the same factors can also improve the results for the LMC. In particular, we show that by modifying the massive stars yields of Mg and Al the behaviour of the [Mg/Mn] vs. [Al/Fe] plot changes substantially. In conclusion, by changing the yields within their error bars, one obtains trends which differ strongly, making it difficult to draw any reliable conclusion on the SFH of galaxies. The proposed diagram is therefore uncertain from a theoretical point of view and it could represent a good diagnostic for SFH if the uncertainties on the nucleosynthesis of these elements (Mg, Mn, Al and Fe) could be reduced by future stellar calculations.

astro-ph.GA↗
arXiv2023

Modeling the chemical enrichment history of the Bulge Fossil Fragment Terzan 5

Terzan 5 is a heavily obscured stellar system located in the inner Galaxy. It has been postulated to be a stellar relic, a Bulge Fossil Fragment witnessing the complex history of the assembly of the Milky Way bulge. In this paper, we follow the chemical enrichment of a set of putative progenitors of Terzan 5 to assess whether the chemical properties of this cluster fit within a formation scenario in which it is the remnant of a primordial building block of the bulge. We can explain the metallicity distribution function and the runs of different element-to-iron abundance ratios as functions of [Fe/H] derived from optical-infrared spectroscopy of giant stars in Terzan 5, by assuming that the cluster experienced two major star formation bursts separated by a long quiescent phase. We further predict that the most metal-rich stars in Terzan 5 are moderately He-enhanced and a large spread of He abundances in the cluster, Y = 0.26-0.335. We conclude that current observations fit within a formation scenario in which Terzan 5 originated from a pristine, or slightly metal-enriched, gas clump about one order of magnitude more massive than its present-day mass. Losses of gas and stars played a major role in shaping Terzan 5 the way we see it now. The iron content of the youngest stellar population is better explained if the white dwarfs that give rise to type Ia supernovae (the main Fe factories) sink towards the cluster center, rather than being stripped by the strong tidal forces exerted by the Milky Way in the outer regions.

astro-ph.GA↗
arXiv2023

Evolution of radioactive elements in the LMC: predictions for future gamma-ray surveys

Short-lived radionuclides, such as 26Al and 60Fe, are tracers of star formation. Therefore, their abundances can unravel the recent star formation history of the host galaxy. In view of future gamma-ray surveys, we predict the masses and fluxes of these two elements in the Large Magellanic Cloud (LMC) using new chemical evolution models. Our best model reproduces the abundance patterns of alpha/Fe ratios, the gas mass, the average metallicity, the present time supernova and nova rates observed in LMC. We show three main results: i) the best model for the LMC suggests a star formation rate very mild at the beginning with a recent burst, and a Salpeter-like initial mass function. ii) The predicted mass of 26Al is 0.33 M_Sun, 2/3 produced by massive stars and 1/3 by novae. iii) The predicted mass of 60Fe is 0.44 M_Sun, entirely produced by massive stars. This result suggests a larger fraction of 60Fe, at variance with the Milky Way. The explanation for this lies in the adopted initial mass function, that for the LMC contains more massive stars than for the Milky Way. These predictions can be useful for the COSI-SMEX mission planned for launch in 2027. The expected gamma-ray line fluxes for the 1.809 MeV line of 26Al and the 1.173 and 1.332 MeV lines of 60Fe are in the range of (0.2-2.7)x10^-6 ph cm^-2 s^-1 and (0.7-2.8)x10^-7 ph cm^-2 s^-1, respectively. This new instrument could have the sensitivity to detect the upper end of the predicted 1.8 MeV flux within its nominal two-year mission.

astro-ph.GA↗
arXiv2023

Origin of neutron capture elements with the Gaia-ESO survey: the evolution of s- and r-process elements across the Milky Way

We study the abundance patterns and the radial gradients of s-process elements (Y, Zr, Ba, La and Ce), r-process elements (Eu) and mixed-process elements (Mo, Nd and Pr) in the Galactic thin disc by means of a detailed two-infall chemical evolution model for the Milky Way with state-of-the-art nucleosynthesis prescriptions. We consider r-process nucleosynthesis from merging neutron stars (MNS), magneto-rotational supernovae (MR-SNe) and s-process synthesis from low- and intermediate- mass stars (LIMS) and rotating massive stars. The predictions of our model are compared with data from the sixth data release of the Gaia-ESO survey, from which we consider 62 open clusters with age > 0.1 Gyr and 1300 Milky Way disc field stars. We conclude that: i) the [Eu/Fe] vs. [Fe/H] is reproduced by both a prompt and a delayed source, but the quick source completely dominates the Eu production; ii) rotation in massive stars contribute substantially to the s-process elements of the first peak, but MNS and MR-SNe are necessary in order to reproduce the observations; iii) due to the adopted yields, our model overpredicts Pr and underpredicts Nd, while the [Mo/Fe] vs. [Fe/H] is nicely reproduced. For the radial gradients, we conclude that: i) our predicted slope of the [Fe/H] gradient is in agreement with the one observed in open clusters by Gaia-ESO and other high-resolution spectroscopic surveys. ii) The predicted slope of the [Eu/H] radial gradient is steeper than the observed one, independently on how quick the production of Eu is. We discuss the possible causes of this discrepancy in terms of both different Galaxy formation scenarios and stellar radial migration effects. iii) For all the elements belonging to the second s-process peak (Ba, La, Ce) as well as for Pr, we predict a plateau at low Galactocentric distances, which is probably due to the enhanced enrichment from LIMS in the inner regions.

astro-ph.GA↗
arXiv2023

GalCEM I -- An Open-Source Detailed Isotopic Chemical Evolution Code

This is the first of a series of papers that will introduce a user-friendly, detailed, and modular GALactic Chemical Evolution Model, GalCEM, that tracks isotope masses as a function of time in a given galaxy. The list of tracked isotopes automatically adapts to the complete set provided by the input yields. The present iteration of GalCEM tracks 86 elements broken down in 451 isotopes. The prescription includes massive stars, low-to-intermediate mass stars, and Type Ia supernovae as enrichment channels. We have developed a preprocessing tool that extracts multi-dimensional interpolation curves from the input yield tables. These interpolation curves improve the computation speeds of the full convolution integrals, which are computed for each isotope and for each enrichment channel. We map the integrand quantities onto consistent array grids in order to perform the numerical integration at each time step. The differential equation is solved with a fourth-order Runge-Kutta method. We constrain our analysis to the evolution of all the light and intermediate elements from carbon to zinc, and lithium. Our results are consistent up to the extremely metal poor regime with Galactic abundances. We provide tools to track the mass rate change of individual isotopes on a typical spiral galaxy with a final baryonic mass of $5\times 10^{10} M_{\odot}$. Future iterations of the work will extend to the full periodic table by including the enrichment from neutron-capture channels as well as spatially-dependent treatments of galaxy properties. GalCEM is publicly available at https://github.com/egjergo/GalCEM/

astro-ph.GA↗
arXiv2022

Chemical evolution of elliptical galaxies I: supernovae and AGN feedback

We study the formation and evolution of elliptical galaxies and how they suppress star formation and maintain it quenched. A one-zone chemical model which follows in detail the time evolution of gas mass and its chemical abundances during the active and passive evolution, is adopted. The model includes both gas infall and outflow as well as detailed stellar nucleosynthesis. Elliptical galaxies with different infall masses, following a down-sizing in star formation scenario, are considered. In the chemical evolution simulation we include a novel calculation of the feedback processes. We include heating by stellar wind, core-collapse SNe, Type Ia SNe (usually not highlighted in galaxy formation simulations) and AGN feedback. The AGN feedback is a novelty in this kind of models and is computed by considering a Bondi-Eddington limited accretion onto the central supermassive black hole. We successfully reproduce several observational features, such as the [$\alpha$/Fe] ratios increasing with galaxy mass, mass-metallicity, $\rm M_{BH}-\sigma$ and $\rm M_{BH}-M_{*}$ relations. Moreover, we show that stellar feedback and in particular Type Ia SNe, has a main role in maintaining quenched the star formation after the occurrence of the main galactic wind, especially in low-mass ellipticals. For larger systems, the contribution from AGN to thermal energy of gas appears to be necessary. However, the effect of the AGN on the development of the main galactic wind is negligible, unless an unreasonable high AGN efficiency or an extremely low stellar feedback are assumed. We emphasize the important role played by Type Ia SNe in the energy budget of early-type galaxies.

astro-ph.GA↗
arXiv2022

[Mg/Fe] ratios in the solar neighbourhood: stellar yields and chemical evolution scenarios

Context. The [Mg/Fe] abundance ratios are a fundamental fossil signature to trace the chemical evolution of the disc. Despite of the huge observational and theoretical effort, discrepancies between models and data are still present and several explanations have been put forward to explain the [$\alpha$/Fe] bimodality. Aims. In this work, we take advantage of a new AMBRE:HARPS dataset, which provides new and more precise [Mg/Fe] estimations, as well as reliable stellar ages for a subsample of stars, to study the evolution of the solar neighbourhood. Methods. The above data are compared with detailed chemical evolution models for the Milky Way, exploring the most used prescriptions for stellar yields and different formation scenarios for the Galactic disc, i.e. the delayed two-infall and the parallel model, also including prescriptions for stellar radial migration. Results. We see that most of the stellar yields struggle to reproduce the observed trend of the data and that semi-empirical yields are still the best to describe the [Mg/Fe] evolution in the thick and thin discs. In particular, most of the yields still predict a steeper decrease of the [Mg/Fe] ratio at high metallicity than what is shown by the data. The bulk of the data are well reproduced by the parallel and two-infall scenarios, but both scenarios have problems in explaining the most metal-rich and metal-poor tails of the low-$\alpha$ data. These tails can be explained in light of radial migration from inner and outer disc regions, respectively. Conclusions. Despite of the evidence of stellar migration, it is difficult to estimate the actual contribution of stars from other parts of the disc to the solar vicinity. However, the comparison between data and models suggests that peculiar histories of star formation, such as that of the two-infall model, are still needed to reproduce the observed distribution of stars.

astro-ph.GA↗