The very first stars that formed in the primordial universe are called Population III stars. They were the first cosmic sources to light up kicking-off the reionization at redshift z ∼ 20-30, i.e. 100-200 million years after the Big Bang. They are also the first sources of metals in the universe: they develop in gas halos with zero or very low metallicity. The objective of this thesis is to illustrate the theoretical models for Pop III formation and subsequently analyze the conditions necessary for their direct detection, which still remains a very complex goal to achieve today. Despite this the James Webb Space Telescope (JWST) is changing this scenario, making the detection of these sources possible. Several physical processes, in particular the gravitational lensing, and spectral and photometric signatures will also be treated, which are considered very important tool for observing distant and faint sources. At the end, it analyze some very recent studies made in a region of interest of the JWST Advanced Deep Extragalactic Survey (JADES), which explores the high-redshift universe, and that reported a possible first detection of these stars.
Le primissime stelle che si sono formate nell’universo primordiale sono chiamate stelle di Popolazione III, sono state le prime luci ad accendersi dando il via all’epoca della reionizzazione a redshift z∼ 20-30, i.e. 100-200 milioni di anni dopo il Big Bang. Sono anche le prime fonti di metalli dell’universo e si sviluppano in aloni di gas con metallicità zero o molto bassa. L’obiettivo di questa tesi è illustrare i modelli teorici di formazione della Pop III e successivamente analizzare le condizioni necessarie per il loro rilevamento diretto, che rimane ancora oggi un traguardo molto complesso da raggiungere. Nonostante ciò, grazie al James Webb Space Telescope (JWST), questo scenario sta cambiando rendendo possibile la detezione di queste sorgenti. Verranno trattati anche diversi processi fisici, in particolare il lensing gravitazionale, e firme spettrali e fotometriche, considerati strumenti importanti per osservare sorgenti lontane e deboli. Infine verranno analizzati alcuni studi recenti svolti in una regione di interesse del JWST Advanced Deep Extragalactic Survey (JADES), che si occupa di esplorare l’universo ad alto redshift, e che ha riportato una prima possibile detezione di queste stelle.
Stelle di popolazione III: teorie di formazione ed osservabilità con i telescopi spaziali di ultima generazione
BISSACCO, ALESSIA
2023/2024
Abstract
The very first stars that formed in the primordial universe are called Population III stars. They were the first cosmic sources to light up kicking-off the reionization at redshift z ∼ 20-30, i.e. 100-200 million years after the Big Bang. They are also the first sources of metals in the universe: they develop in gas halos with zero or very low metallicity. The objective of this thesis is to illustrate the theoretical models for Pop III formation and subsequently analyze the conditions necessary for their direct detection, which still remains a very complex goal to achieve today. Despite this the James Webb Space Telescope (JWST) is changing this scenario, making the detection of these sources possible. Several physical processes, in particular the gravitational lensing, and spectral and photometric signatures will also be treated, which are considered very important tool for observing distant and faint sources. At the end, it analyze some very recent studies made in a region of interest of the JWST Advanced Deep Extragalactic Survey (JADES), which explores the high-redshift universe, and that reported a possible first detection of these stars.File | Dimensione | Formato | |
---|---|---|---|
Bissacco_Alessia.pdf
accesso aperto
Dimensione
4.5 MB
Formato
Adobe PDF
|
4.5 MB | Adobe PDF | Visualizza/Apri |
The text of this website © Università degli studi di Padova. Full Text are published under a non-exclusive license. Metadata are under a CC0 License
https://hdl.handle.net/20.500.12608/80180