Related papers: Abundance determinations in HII regions: model fit…
We present deep optical spectroscopy of eight HII regions located in the anticentre of the Milky Way. The spectra were obtained at the 10.4m GTC and 8.2m VLT. We determined Te([NII]) for all objects and Te([OIII]) for six of them. We also…
Infrared OH lines at 1.55 - 1.56 um in the H-band were obtained with the Phoenix high-resolution spectrograph at the 2.1m telescope of the Kitt Peak National Observatory for a sample of 14 metal-poor stars. Detailed analyses of the sample…
We present two samples of $\hii$ galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release 3. The electron temperatures($T_e$) of 225 galaxies are calculated with the photoionized $\hii$ model and $T_e$ of…
We investigate electron temperature (Te) and gas-phase oxygen abundance (Z_Te) measurements for galaxies in the local Universe (z < 0.25). Our sample comprises spectra from a total of 264 emission-line systems, ranging from individual HII…
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 propose two statistical methods to derive oxygen abundances in HII regions and star forming galaxies and calibrate them with a sample of several hundred giant HII regions in spiral and blue compact galaxies as well as of galaxies from…
We compare the oxygen abundance (O/H) of the Narrow Line Regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the…
The debate on the oxygen abundances of metal-poor stars has its origin in contradictory results obtained using different abundance indicators. To achieve a better understanding of the problem we have acquired high quality spectra with the…
Understanding the complex ionization structure and chemical composition of \hii\ regions poses a significant challenge in astrophysics. The abundance discrepancy problem, characterized by inconsistencies between abundances derived from…
We investigate the discrepancy between oxygen abundance estimations for narrow-line regions (NLRs) of Active Galactic Nuclei (AGNs) type Seyfert 2 derived by using direct estimations of the electron temperature (Te-method) and those derived…
We present the oxygen abundance determination for 90 HII regions in the inner parts of the grand design galaxy M101. The abundances were derived employing the P method (Pilyugin 2001a). A comparison is made with previous determinations…
We investigate relationships between observed auroral and nebular oxygen line fluxes in spectra of HII regions. We find a relation that is metallicity-dependent at low metallicities, but becomes independent of metallicity (within the…
We examine the relation between oxygen abundances in the narrow-line regions (NLRs) of active galactic nuclei (AGNs) estimated from the optical emission lines through the strong-line method (the theoretical calibration of Storchi-Bergmann…
We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…
I present deep spectroscopy of four HII regions in the inner, metal-rich zone of the spiral galaxy M101 obtained with the LRIS spectrograph at the Keck telescope. From the analysis of the collisionally excited lines in two of the target HII…
The metal content of a galaxy is a key property for distinguishing between viable galaxy evolutionary scenarios, and it strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of…
To calibrate the relationship between Ne3O2 (Ne3O2 = log(\neiii$\lambda3869$/\oii$\lambda3727$)) and oxygen abundances, we present a sample of $\sim$3000 $\hii$ galaxies from the Sloan Digital Sky Survey (SDSS) data release four. They are…
The spatial distribution of metals reflects, and can be used to constrain, the processes of chemical enrichment and mixing. Using PHANGS-MUSE optical integral field spectroscopy, we measure the gas phase oxygen abundances (metallicities)…
Aims. We report the results of a novel determination of the solar oxygen abundance using spatially resolved observations and inversions. We seek to derive the photospheric solar oxygen abundance with a method that is robust against…
A detailed spectroscopic study, from lambda 3700 A to 1 um, was performed for a sample of 34 HII galaxies in order to derive fundamental parameters for their HII regions and ionizing sources, as well as gaseous metal abundances. All the…