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Cosmic Chemical and Dust Evolution
- Publication Year :
- 2022
- Publisher :
- Università degli Studi di Trieste, 2022.
-
Abstract
- In this Thesis, we investigate the chemical and dust evolution of the different galactic environments we encounter during the cosmic history, from the high-redshift Universe to the Milky Way. The study of the evolution of galaxies is performed by means of detailed chemical evolution models that predict the abundances of single chemical elements in the interstellar medium as well as the condensation into dust of the chemical elements. In the first part of the Thesis, we concentrate on the study of moderate to high-redshift systems. We start focusing on high-redshift starburst galaxies, whose extreme conditions pose questions on the universality of the initial mass function (IMF) as well as on the processes regulating the ISM dust. For these reasons, we test the the impact of the IMF shape on high-redshift environments by applying the so-called Integrated Galactic IMF (IGIMF) theory in models specifically suited for starburst galaxies. In this way, we look at the interplay between the IMF and dust processes in shaping the observed gas abundance patterns as well as global dust quantities. This analysis highlights the degenerate effect of the IGIMF and dust on abundance patterns and suggests that the IGIMF can explain the dust masses observed in some high-redshift star forming objects. To get a more complete picture about dust through cosmic evolution, we also investigate how dust quantities evolve at larger volume scales. To this aim, we present a novel method to compute the redshift evolution of dust mass in galaxy clusters. This is done by integrating the predictions of chemical and dust evolution models for individual galaxies over the galaxy cluster luminosity function (LF), assuming suitable cosmological scenarios for the LF evolution. By applying this method, we reproduce the dust amounts observed in low and intermediate-redshift galaxy clusters and we answer to some questions about dust in cluster. In particular, we find that spiral galaxies are the most important dust producers within clusters and that galactic ejecta can account alone for the observed intracluster dust. In the second part of the Thesis, instead, we focus on study of the local Universe and in particular of the MW Galaxy. We start investigating the evolution of the MW thick and thin discs by comparing MW models with recent survey data. In particular, we discuss the formation of abundance gradients in the MW and the main physical parameters influencing this process, concluding that inside-out disc formation should act together with radial gas flows and variable efficiency of star formation. Moreover, we suggest that to reproduce the observed [α/Fe] dichotomy/bimodality (i.e., the presence of two distinct data sequences in the [α/Fe] vs. [Fe/H] diagram) at different Galactocentric distances, one should assume a prolonged gap between the formation of the thick and thin discs and a chemically enriched gas accretion in the innermost thin disc. Finally, we study the impact of different Type Ia SN yields on the evolution of Fe-peak elements in our Galaxy. To this aim, we apply to our chemical models for the MW a large compilation of Type Ia SN yields from the recent literature, sampling different explosion mechanisms. The obtained results are compared with those obtained with classical Type Ia SN prescriptions adopted in previous studies. In addition, we allow combinations of of Type Ia SN yields from different progenitor classes to assess their role in terms of the chemical enrichment. We find that the chemical abundance patterns strongly depend not only on the explosion mechanism but also on other conditions. Moreover, the comparison with the observed abundance trends suggests that a combination of different classes of explosion is necessary to reproduce the data. In this Thesis, we investigate the chemical and dust evolution of the different galactic environments we encounter during the cosmic history, from the high-redshift Universe to the Milky Way. The study of the evolution of galaxies is performed by means of detailed chemical evolution models that predict the abundances of single chemical elements in the interstellar medium as well as the condensation into dust of the chemical elements. In the first part of the Thesis, we concentrate on the study of moderate to high-redshift systems. We start focusing on high-redshift starburst galaxies, whose extreme conditions pose questions on the universality of the initial mass function (IMF) as well as on the processes regulating the ISM dust. For these reasons, we test the the impact of the IMF shape on high-redshift environments by applying the so-called Integrated Galactic IMF (IGIMF) theory in models specifically suited for starburst galaxies. In this way, we look at the interplay between the IMF and dust processes in shaping the observed gas abundance patterns as well as global dust quantities. This analysis highlights the degenerate effect of the IGIMF and dust on abundance patterns and suggests that the IGIMF can explain the dust masses observed in some high-redshift star forming objects. To get a more complete picture about dust through cosmic evolution, we also investigate how dust quantities evolve at larger volume scales. To this aim, we present a novel method to compute the redshift evolution of dust mass in galaxy clusters. This is done by integrating the predictions of chemical and dust evolution models for individual galaxies over the galaxy cluster luminosity function (LF), assuming suitable cosmological scenarios for the LF evolution. By applying this method, we reproduce the dust amounts observed in low and intermediate-redshift galaxy clusters and we answer to some questions about dust in cluster. In particular, we find that spiral galaxies are the most important dust producers within clusters and that galactic ejecta can account alone for the observed intracluster dust. In the second part of the Thesis, instead, we focus on study of the local Universe and in particular of the MW Galaxy. We start investigating the evolution of the MW thick and thin discs by comparing MW models with recent survey data. In particular, we discuss the formation of abundance gradients in the MW and the main physical parameters influencing this process, concluding that inside-out disc formation should act together with radial gas flows and variable efficiency of star formation. Moreover, we suggest that to reproduce the observed [α/Fe] dichotomy/bimodality (i.e., the presence of two distinct data sequences in the [α/Fe] vs. [Fe/H] diagram) at different Galactocentric distances, one should assume a prolonged gap between the formation of the thick and thin discs and a chemically enriched gas accretion in the innermost thin disc. Finally, we study the impact of different Type Ia SN yields on the evolution of Fe-peak elements in our Galaxy. To this aim, we apply to our chemical models for the MW a large compilation of Type Ia SN yields from the recent literature, sampling different explosion mechanisms. The obtained results are compared with those obtained with classical Type Ia SN prescriptions adopted in previous studies. In addition, we allow combinations of of Type Ia SN yields from different progenitor classes to assess their role in terms of the chemical enrichment. We find that the chemical abundance patterns strongly depend not only on the explosion mechanism but also on other conditions. Moreover, the comparison with the observed abundance trends suggests that a combination of different classes of explosion is necessary to reproduce the data.
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.dedup.wf.001..40bd12ccd9e491806fbb6cc62eaf5ea3