Related papers: Carbon Nitrogen, and Oxygen Galactic Gradients: A …
We discuss the evolution of oxygen, carbon and nitrogen in galaxies of different morphological type by adopting detailed chemical evolution models with different star formation histories (continuous star formation or starbursts). We start…
Multi-zone chemical evolution models (CEMs), differing in the nucleosynthesis prescriptions (yields) and prescriptions of star formation, have been computed for the Milky Way. All models fit the observed O/H and Fe/H gradients well and…
Chemical evolution models for the Galactic disk under an inside-out formation scenario are presented for seven sets of stellar yields, all of them metal dependent. In particular, the effects of yields from massive and…
We present chemical evolution models of the Galactic disk with different Z-dependent yields. We find that a moderate mass loss rate for massive stars of solar metallicity produces an excellent fit to the observed C/H and C/O gradients of…
We analyze the behavior of N/O and C/O abundance ratios as a function of metallicity as gauged by O/H in large, extant Galactic and extragalactic H II region abundance samples. Numerical chemical evolution models are computed using…
We present C and O abundances in the Magellanic Clouds derived from deep spectra of HII regions. The data have been taken with the Ultraviolet-Visual Echelle Spectrograph at the 8.2-m VLT. The sample comprises 5 HII regions in the Large…
Ultraviolet nebular emission lines are important for understanding the time evolution and nucleosynthetic origins of their associated elements, but the underlying trends of their relative abundances are unclear. We present UV spectroscopy…
The study of carbon and oxygen abundances yields information on the time evolution and nucleosynthetic origins of these elements, yet remains relatively unexplored. At low metallicities (12+log(O/H) < 8.0), nebular carbon measurements are…
We present deep spectrophotometry of 18 HII regions in the nearby massive spiral galaxies M101 and M31. We have obtained direct determinations of electron temperature in all the nebulae. We detect the CII 4267 line in several HII regions,…
Using the standard infall model of Galactic chemical evolution, we explore the origin of carbon and calculate the abundance evolution of CNO elements for 8 different models of stellar nucleosynthesis yields. The results show that, in the…
We employ analytical and numerical chemical evolution models to study observed trends in abundance ratios involving carbon, nitrogen, and oxygen. Several sets of published stellar yields for both intermediate-mass and massive stars are…
Precise determinations of the chemical composition in early B-type stars consitute fundamental observational constraints on stellar and galactochemical evolution. Carbon is one of the most abundant metals in the Universe but analyses in…
We derive empirical constraints on the nucleosynthetic yields of nitrogen by incorporating N enrichment into our previously developed and empirically tuned multi-zone galactic chemical evolution model. We adopt a metallicity-independent…
The main objective of the present work is to ckeck if the star formation efficiency plays a relevant role in the evolution of the relative abundance N/O. We analyze the evolution of the nitrogen-to-oxygen ratio as predicted by a set of…
We present chemical evolution models aimed at reproducing the observed (N/O) vs. (O/H) abundance pattern of star forming galaxies in the Local Universe. We derive gas-phase abundances from SDSS spectroscopy and a complementary sample of…
The evolution of C and O abundances in the Milky Way can impose strong constraints on stellar nucleosynthesis and help understanding the formation and evolution of our Galaxy. The aim is to review the measured C and O abundances in the disk…
We present a set of low and intermediate mass star yields based on a modeling of the TP--AGB phase which affects the production of nitrogen and carbon. These yields are evaluated by using them in a Galaxy Chemical Evolution model, with…
We study the redshift evolution of the gas-phase O/H and N/O abundances, both (i) for individual ISM regions within single spatially-resolved galaxies and (ii) when dealing with average abundances in the whole ISM of many unresolved…
We present two chemical evolution models of our galaxy, both models are built to fit the O/H ratios derived from H II regions, using two different methods. One model is based on abundances obtained from the [O III] 4363/5007 temperatures…
We present measurements of the gas-phase C/O abundance ratio in six H II regions in the spiral galaxies M101 and NGC 2403, based on ultraviolet spectroscopy using the Faint Object Spectrograph on the Hubble Space Telescope. The C/O ratios…