Related papers: A New Contributor to Chemical Evolution in High-Re…
Supernovae play a large but poorly understood role in our attempts to explain the evolution of the baryonic universe. Numerous observations throughout astronomy cannot be explained if we neglect their influence, yet our quantitative…
While the chemical abudances observed in bright planetary nebulae in local spiral galaxies are less varied than their counterparts in dwarfs, they provide new insight. Their helium abundances are typically enriched by less than 50\%…
We present chemical abundances in K and M red-giant members of the Galactic bulge derived from high-resolution infrared spectra obtained with the Phoenix spectrograph on Gemini-South. The elements studied are carbon, nitrogen, oxygen,…
Some aspects of the chemical evolution of late-type dwarf galaxies are reviewed, together with their implications on three issues of cosmological relevance: similarity to primeval galaxies, derivation of the primordial helium abundance,…
Spectroscopic observations of distant cosmological sources continue to exhibit a surprising result; that the chemical abundance of the universe seems to be approximately solar for the observed sources at redshifts of 5, 6, and even 7, even…
All types of supernovae (SNe), except Type Ia, have been observed to interact with their immediate circumstellar medium (CSM). This interaction can reveal their progenitor's histories, and constrain our ideas about the evolution of massive…
We simulate cosmic chemical enrichment with a hydrodynamical model including supernova and hypernova feedback. We find that the majority of stars in present-day massive galaxies formed in much smaller galaxies at high redshifts, despite…
We have collected an heterogeneous sample of galaxies at redshifts 0.001<z<3.35 with the aim of exploring the evolution of the physical parameters and of the element abundances calculated by modelling the observed spectra. The evolution…
We introduce a metallicity dependence of Type Ia supernova (SN Ia) rate into the Galactic and cosmic chemical evolution models. In our SN Ia progenitor scenario, the accreting white dwarf (WD) blows a strong wind to reach the Chandrasekhar…
Almost since the beginning, massive stars and their resultant supernovae have played a crucial role in the Universe. These objects produce tremendous amounts of energy and new, heavy elements that enrich galaxies, encourage new stars to…
We analyze the influence of the evolution of light absorption by gray dust in the host galaxies of type Ia supernovae (SNe Ia) and the evolution of the mean combined mass of close-binary carbon-oxygen white dwarfs merging due to…
I present a new Galactic chemical evolution model motivated by and grounded in the hierarchical theory of galaxy formation, as expressed by a halo merger history of the Galaxy. This model accurately reproduces the "metallicity distribution…
We present gas-phase elemental abundance ratios of 7 local extremely metal-poor galaxies (EMPGs) including our new Keck/LRIS spectroscopy determinations together with 33 JWST $z\sim 4-10$ star-forming galaxies in the literature, and compare…
In this paper we study the impact of nova nucleosynthesis on models for the chemical evolution of the Galaxy. It is found that novae are likely to be the sources of non-negligible fractions of the 7Li and 13C observed in disc stars.…
Recent work presented increasing evidence of high, non-constant S/O abundance ratios observed in star-forming metal-poor galaxies, showing deviations from the constant canonical S/O across a large range of O/H abundance. Similar peculiar…
We have investigated the oxygen and nitrogen chemical abundances in extremely compact star-forming galaxies with redshifts between $\sim$0.11-0.35, popularly referred to as "green peas". Direct and strong-line methods sensitive to the N/O…
Recent JWST observations have revealed a growing population of galaxies at $z>4$ with elevated nitrogen-to-oxygen ratios. These "N/O-enhanced" galaxies (NOEGs) exhibit near- to super-solar N/O at sub-solar O/H, clearly deviating from the…
Chemical enrichment signatures strongly constrain galaxy formation and evolution, and a detailed understanding of abundance patterns provides clues regarding the nucleosynthetic production pathways of elements. Using the SDSS-IV MaNGA IFU…
Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g. stellar radiation, winds or explosions, or by their environment. While the metallicity depletion…
Type Ia supernovae (SNe Ia) play key roles in revealing the accelerating expansion of the universe, but our knowledge about their progenitors is still very limited. Here we report the discovery of a rigid dichotomy in circumstellar (CS)…