5 papers
Investigating the electron temperature of [Ar IV] in planetary nebulae using the DESIRED database
J. GarcÃa-Rojas, E. Reyes-RodrÃguez, J. E. Méndez-Delgado +9
(Abridged) We investigate the behaviour of the electron temperature derived from [Ar IV] lines, Te([Ar IV]), in a sample of PNe to characterize the thermal structure of high-excita…
Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Northern Local Star-forming Dwarf Galaxies. Analogues of the First Galaxies and Probes of the Cosmic Metallicity Scale
C. Esteban, J. M. Vilchez, J. GarcÃa-Rojas +15
Star-forming dwarf galaxies in the local Universe, especially extremely metal-poor ones, can be considered analogous to early galaxies of the Epoch of Reionization (z >= 6). Curren…
Alpha-element abundance patterns in star-forming regions of the local Universe
C. Esteban, J. E. Méndez-Delgado, J. GarcÃa-Rojas +6
(Abridged) We reassess the alpha-element abundance ratios (Ne/O, S/O, Ar/O) with respect to metallicity in ~1000 spectra of Galactic and extragalactic HII regions and star-forming…
Generalized ([OIII])-(HeI) Discrepancies in Ionized Nebulae: Possible Evidence of Case B Deviations and Temperature Inhomogeneities
J. E. Méndez-Delgado, E. D. Skillman, E. Aver +11
The physics of recombination lines (RLs) in the HeI singlet system is expected to be relatively simple, supported by accurate atomic models. We examine the intensities of HeI singl…
Chlorine abundances in star-forming regions of the local Universe
M. Orte-GarcÃa, C. Esteban, J. E. Méndez-Delgado +4
Aims. We study the behaviour of Cl abundance and its ratios with respect to O, S and Ar abundances in a sample of more than 200 spectra of Galactic and extragalactic H ii regions a…