76 citations · 250 across the 15 of their papers we have counts for
15 papers
Investigating the electron temperature of [Ar IV] in planetary nebulae using the DESIRED database
J. García-Rojas, E. Reyes-Rodríguez, 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. García-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…
Chlorine abundances in star-forming regions of the local Universe
M. Orte-García, 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…
Alpha-element abundance patterns in star-forming regions of the local Universe
C. Esteban, J. E. Méndez-Delgado, J. García-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…
Gas-phase Fe/O and Fe/N abundances in Star-Forming Regions. Relations between nucleosynthesis, metallicity and dust
J. E. Méndez-Delgado, K. Kreckel, C. Esteban +10
In stars, metallicity is usually traced using Fe, while in nebulae, O serves as the preferred proxy. Both elements have different nucleosynthetic origins and are not directly compa…
Excitation mechanisms of C II optical permitted lines in ionized nebulae
E. Reyes-Rodríguez, J. E. Méndez-Delgado, J. García-Rojas +4
Context. Carbon is the fourth most abundant element in the universe and its distribution is critical to understanding stellar evolution and nucleosynthesis. In optical studies of i…
Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy II: HH204
J. E. Méndez-Delgado, W. J. Henney, C. Esteban +3
We analyze the physical conditions, chemical composition and other properties of the photoionized Herbig-Haro object HH~204 through Very Large Telescope (VLT) echelle spectroscopy…
The chemical composition of Galactic ring nebulae around massive stars
C. Esteban, A. Mesa-Delgado, C. Morisset +1
We present deep spectra of ring nebulae associated with Wolf-Rayet (WR) and O-type stars: NGC 6888, G2.4+1.4, RCW 58, S 308, NGC 7635 and RCW 52. The data have been taken with the…
The Fe/Ni ratio in ionized nebulae: clues on dust depletion patterns
Gloria Delgado-Inglada, Adal Mesa-Delgado, Jorge García-Rojas +2
We perform a homogeneous analysis of the Fe/Ni abundance ratio in eight Galactic planetary nebulae (PNe) and three Galactic H II regions that include the Orion nebula, where we stu…
The radial abundance gradient of chlorine in the Milky Way
C. Esteban, J. Garcia-Rojas, V. Perez-Mesa
We determine the radial abundance gradient of Cl in the Milky Way from HII regions spectra. For the first time, the Cl/H ratios are computed by simply adding ionic abundances and n…
Deep high spectral resolution spectroscopy and chemical composition of ionized nebulae
C. Esteban, J. Garcia-Rojas, A. Mesa-Delgado +1
High spectral resolution spectroscopy has proved to be very useful for the advancement of chemical abundances studies in photoionized nebulae, such as H II regions and planetary ne…
NGC 2579 and the carbon and oxygen abundance gradients beyond the solar circle
C. Esteban, L. Carigi, M. V. F. Copetti +4
We present deep echelle spectrophotometry of the Galactic HII region NGC 2579. The data have been taken with the Very Large Telescope Ultraviolet-Visual Echelle Spectrograph in the…
Exploring the effects of high-velocity flows in abundance determinations in H II regions. Bidimensional spectroscopy of HH 204 in the Orion Nebula
M. Núñez-Díaz, A. Mesa-Delgado, C. Esteban +3
We present results from integral field optical spectroscopy with the Potsdam Multi-Aperture Spectrograph of the Herbig-Haro (HH) object HH 204, with a spatial sampling of 1 x 1 arc…
Integral field spectroscopy of selected areas of the Bright Bar and Orion-S cloud in the Orion Nebula
A. Mesa-Delgado, M. Núñez-Díaz, C. Esteban +2
We present integral field spectroscopy of two selected zones in the Orion Nebula obtained with the Potsdam Multi-Aperture Spectrophotometer (PMAS), covering the optical spectral ra…