相关论文: Metallicity measurements in AGNs
We revisit the evolution of the mass-metallicity relation of low- and high-redshift galaxies by using a sample of local analogs of high-redshift galaxies. These analogs share the same location of the UV-selected star-forming galaxies at…
Spatially resolved gas-phase metallicity maps are a crucial element in understanding the chemical evolution of galaxies. We present spatially resolved metallicity maps obtained from NIRISS/WFSS observations. This is the first such work…
Metallicity measurements in galaxies can give valuable clues about galaxy evolution. One of the mechanisms postulated for metallicity redistribution in galaxies is gas flows induced by AGN, but the details of this process remain elusive. We…
We present long-slit observations in the optical and near infrared of fourteen HII regions in the spiral galaxies: NGC 628, NGC 925, NGC 1232 and NGC 1637, all of them reported to have solar or oversolar abundances according to empirical…
We present the mass-metallicity relation for star-forming galaxies in the MUSE Quasar Nebula 01 (MQN01) field, a massive cosmic web node at $z \sim 3.245$, hosting one of the largest overdensities of galaxies and AGNs found so far at $z >…
Resolved measurements of gas-phase metallicities in galaxies that both do and do not host active galactic nuclei (AGN) are crucial for understanding the role of AGN in regulating galaxy growth over cosmic time. Recent work at $z=0$ has…
The O/H metallicity distribution of different samples of planetary nebulae in the bulge of the Milky Way and M31 are compared. O/H abundances are converted into [Fe/H] metallicity by the use of theoretical [O/Fe] x [Fe/H] relationships both…
We report the first survey of chemical abundances in M and K dwarf stars using atomic absorption lines in high resolution spectra. We have measured Fe and Ti abundances in 35 M and K dwarf stars using equivalent widths measured from (lambda…
A growing number of indicators are now being used with some confidence to measure the metallicity(Z) of photoionisation regions in planetary nebulae, galactic HII regions(GHIIRs), extra-galactic HII regions(EGHIIRs) and HII galaxies(HIIGs).…
We study the hypothesis of high metallicity clumps being responsible for the abundance discrepancy found in planetary nebulae between the values obtained from recombination and collisionaly excited lines. We generate grids of…
Using ab-initio photoionization models of giant HII regions, we test methods for abundance determinations based on a direct measurement of the electron temperature, now possible even for moderate to high-metallicity objects. We find that,…
Recent JWST observations have revealed a population of high-redshift galaxies ($z\gtrsim5$) exhibiting unexpectedly bright ultraviolet (UV) nitrogen emission lines. The strong N III] and N IV] features imply nitrogen-to-oxygen abundance…
We present a method to determine nitrogen abundance ratios with respect to iron ([N/Fe]) from molecular CN-band features observed in low-resolution ($R \sim$ 2000) stellar spectra obtained by the Sloan Digital Sky Survey (SDSS) and the…
Gas-phase metallicity is a fundamental parameter that helps constrain the star-forming history and chemical evolution of a galaxy. Measuring electron temperature through auroral-to-strong line ratios is a direct approach to deriving…
We derive metal abundance estimates for a large sample of starbursting emission-line galaxies (ELGs). Our sample is drawn from the KPNO International Spectroscopic Survey (KISS) which has discovered over 2000 ELG candidates to date.…
Despite advances in observational data, theoretical models, and computational techniques to simulate key physical processes in the formation and evolution of galaxies, the stellar mass assembly of galaxies still remains an unsolved problem…
Using Hubble Space Telescope ultraviolet and ground-based optical spectroscopy, we measure the C/O and N/O ratios of three metal-poor galaxies with similar metallicity but differing N/O. The C/O ratios estimated from C III] lambda1909 and…
We have derived Mn abundances for more than 200 stars in 19 globular clusters. In addition, Mn abundance determinations have been made for a comparable number of halo field and disk stars possessing an overlapping range of metallicities and…
I present a review of chemical evolution models of the solar neighborhood. I give special attention to the necessary ingredients to reproduce the observed [Xi/Fe] ratios in nearby metal and super metal rich stars, and to the chemical…
The mass-metallicity relation (MZR) of type-2 active galactic nuclei (AGNs) at 1.2 < z < 4.0 is investigated by using high-z radio galaxies (HzRGs) and X-ray selected radio-quiet AGNs. We combine new rest-frame ultraviolet (UV) spectra of…