I will give a brief summary on the origin of elements using Galactic chemical evolution with Pop II and Pop I stars. Then I will discuss the Pop III nucleosynthesis using extremely metal-poor stars in the Milky Way. Namely, I will present our new analysis with machine learning to find “the first stars were not alone”. Finally, I will discuss the first chemical enrichment in the Universe,...
GRB are produced by massive stars. Several studies considered the possibility of PoPIII stars as GRB progenitors and predicted the GRB properties. Furthermore GRB afterglows are bright at any redshift and can be used as background sources to study the absorbing gas in their host galaxies and along GRB lines of sight up to the highest redshift, looking for signatures of pristine gas or gas...
I will present the study of the abundances of the chemical elements present in the gas associated with cosmological structures at redshift ~6. The goal is to look for the nucleosynthetic traces of the Pop III stars and, more generally, to understand which generation of stars contributed to the enrichment of metals in the gas of galaxies at that time.
To determine these abundances, we studied...
The properties of the first (Pop. III) stars remain a mystery. The chemistry of relic environments, enriched only by the supernovae of these first stars, offer an exciting avenue to study this population. Stellar relics are often found in the local Universe while gaseous relics probe the chemistry of low density structures at earlier epochs (z>2). I will discuss the complementary nature of...
Quasar absorption line systems are an excellent probe of chemical evolution across time. In absorption line systems associated with the interstellar and circumgalactic medium of galaxies, the column densities of gas are sufficiently high that detailed and accurate chemical abundance patterns can be obtained and compared to complimentary stellar abundance analyses. These detailed chemical...
The first stars were born from chemically pristine gas. They were likely massive and thus they rapidly exploded as supernovae, enriching the surrounding gas with heavy elements.
The nature of first stars can be studied locally, investigating the chemical properties of ancient metal-poor stars in the Milky Way halo and in Local Group dwarf galaxies. Indeed, here we observe low-mass, long-lived...
