activity
20192026
most citedTemperature inhomogeneities cause the abundance discrepancy in H II regions

58 citations · 274 across the 24 of their papers we have counts for

collaborators

24 papers

astro-ph.GA2026

A Broken Clock Is Right Twice a Day: [Ce/Mg] Is Not a Universal Chemical Clock

Liam O. Dubay, Jennifer A. Johnson, James W. Johnson +14

The ratio of -process to -element enrichment () has been proposed as a ``chemical clock,'' or a means to estimate stellar ages. However, the age-- relation vari…

astro-ph.GA2026

The Open Cluster Chemical Abundances and Mapping Survey XI. First Gradients from SDSS/MWM BOSS Determined Clusters

Jonah M. Otto, Peter M. Frinchaboy, John Donor +13

The Milky Way Mapper program in the fifth generation of the Sloan Digital Sky Survey (SDSS-V/MWM) has observed millions of stars, thousands of them in open clusters. The Open Clust…

astro-ph.GA2026

SDSS-V LVM: Verifying what, and where, the 'Galactic Center' Lobe is

K. Kreckel, O. V. Egorov, N. Drory +23

The so-called 'Galactic Center' Lobe (GCL) is an extended (~1 deg) radio continuum feature situated above the Galactic Plane, for which the literature contains varying claims about…

astro-ph.GA2025

Resolved HII regions in NGC 253: Ionized gas structure and suggestions of a universal density-surface brightness relation

Rebecca L. McClain, Adam K. Leroy, Enrico Congiu +23

We use the full-disk VLT-MUSE mosaic of NGC 253 to identify 2492 HII regions and study their resolved structure. With an average physical resolution of 17 pc, this is one of the la…

astro-ph.GA2025★ 4 cited

SDSS-V Local Volume Mapper (LVM): Revealing the Structure of the Rosette Nebula

Mónica A. Villa-Durango, Jorge Barrera-Ballesteros, Carlos G. Román-Zúñiga +19

The Rosette Nebula is a well-known H II region shaped by the interaction of gas with the OB stars of the NGC 2244 stellar association. Located within the remnant of a giant molecul…

astro-ph.SR2025

Atmospheric parameters and chemical abundances of young stars with APOGEE. I. Orion star-forming region

Ricardo López-Valdivia, Lucía Adame, Carlos G. Román-Zúñiga +19

We derive atmospheric parameters and chemical abundances in young G-, K-, and M-type stars (temperatures between 6500 and 3100 K) using infrared APOGEE-2 spectra. Atmospheric param…

astro-ph.GA2025

The impact of spiral arms on the star formation life cycle

Andrea Romanelli, Mélanie Chevance, J. M. Diederik Kruijssen +18

The matter cycle between gas clouds and stars in galaxies plays a crucial role in regulating galaxy evolution through feedback mechanisms. In turn, the local and global galactic en…

astro-ph.GA2024★ 1 cited

Analyzing the Abundance Discrepancy Problem in HII Regions with Photoionization Modeling

Ahmad Nemer, J. E. Mendez-Delgado, Natascha Sattler +5

Understanding the complex ionization structure and chemical composition of \hii\ regions poses a significant challenge in astrophysics. The abundance discrepancy problem, character…

astro-ph.GA2024

PHANGS-ML: the universal relation between PAH band and optical line ratios across nearby star-forming galaxies

Dalya Baron, Karin Sandstrom, Jessica Sutter +22

The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain propert…

astro-ph.GA2024★ 2 cited

The SDSS-V Local Volume Mapper (LVM): Scientific Motivation and Project Overview

Niv Drory, Guillermo A. Blanc, Kathryn Kreckel +48

We present the Sloan Digital Sky Survey V (SDSS-V) Local Volume Mapper (LVM). The LVM is an integral-field spectroscopic survey of the Milky Way, Magellanic Clouds, and of a sample…

astro-ph.GA2024★ 24 cited

SDSS-V Local Volume Mapper (LVM): A Glimpse into Orion

K. Kreckel, O. V. Egorov, E. Egorova +37

The Orion Molecular Cloud complex, one of the nearest (D = 406 pc) and most extensively studied massive star-forming regions, is ideal for constraining the physics of stellar feedb…

astro-ph.GA2024

H-alpha emission and HII regions at the locations of recent supernovae in nearby galaxies

Ness Mayker Chen, Adam K. Leroy, Sumit K. Sarbadhicary +22

We present a statistical analysis of the local, approximately 50-100 pc scale, H-alpha emission at the locations of recent (less than 125 years) supernovae (SNe) in nearby star-for…

astro-ph.GA2024

PHANGS-ML: dissecting multiphase gas and dust in nearby galaxies using machine learning

Dalya Baron, Karin M. Sandstrom, Erik Rosolowsky +25

The PHANGS survey uses ALMA, HST, VLT, and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions of spatially independent regions. The high dim…

astro-ph.GA2024★ 1 cited

PHANGS-JWST: Data Processing Pipeline and First Full Public Data Release

Thomas G. Williams, Janice C. Lee, Kirsten L. Larson +55

The exquisite angular resolution and sensitivity of JWST is opening a new window for our understanding of the Universe. In nearby galaxies, JWST observations are revolutionizing ou…

astro-ph.GA2023

Investigating the Drivers of Electron Temperature Variations in HII Regions with Keck-KCWI and VLT-MUSE

Ryan J. Rickards Vaught, Karin M. Sandstrom, Francesco Belfiore +12

HII region electron temperatures are a critical ingredient in metallicity determinations and recent observations reveal systematic variations in the temperatures measured using dif…

astro-ph.GA2023★ 55 cited

Density biases and temperature relations for DESIRED HII regions

J. E. Méndez-Delgado, C. Esteban, J. García-Rojas +6

We present a first study based on the analysis of the DEep Spectra of Ionized REgions Database (DESIRED). This is a compilation of 190 high signal-to-noise ratio optical spectra of…

astro-ph.GA2023★ 58 cited

Temperature inhomogeneities cause the abundance discrepancy in H II regions

J. Eduardo Méndez-Delgado, César Esteban, Jorge García-Rojas +2

HII regions, ionized nebulae where massive star formation has taken place, exhibit a wealth of emission lines that are the fundamental basis for estimating the chemical composition…

astro-ph.GA2023★ 18 cited

Atomic Data Assessment with PyNeb: Radiative and Electron Impact Excitation Rates for [Fe II] and [Fe III]

Claudio Mendoza, José E. Méndez-Delgado, Manuel Bautista +2

We use the PyNeb 1.1.16 Python package to evaluate the atomic datasets available for the spectral modeling of [Fe II] and [Fe III], which list level energies, A-values, and effecti…

astro-ph.GA2022★ 5 cited

Backscattering and Line Broadening in Orion

C. R. O'Dell, G. J. Ferland, J. E. Mendez-Delgado

Examination of emission lines in high-velocity resolution optical spectra of the Orion Nebula confirms that the velocity component on the red wing of the main ionization front emis…

astro-ph.GA2022★ 33 cited

About Metallicity Variations in the Local Galactic Interstellar Medium

C. Esteban, J. E. Méndez-Delgado, J. García-Rojas +1

In this paper we discuss and confront recent results on metallicity variations in the local interstellar medium, obtained from observations of HII regions and neutral clouds of the…

astro-ph.GA2021★ 21 cited

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…

astro-ph.GA2021★ 28 cited

Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy I: HH529II and III

J. E. Méndez-Delgado, C. Esteban, J. García-Rojas +3

We present the analysis of physical conditions, chemical composition and kinematic properties of two bow shocks -HH529 II and HH529 III- of the fully photoionized Herbig-Haro objec…

astro-ph.SR2020★ 23 cited

Helium abundances and its radial gradient from the spectra of HII regions and ring nebulae of the Milky Way

J. E. Méndez-Delgado, C. Esteban, J. García-Rojas +2

We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 regions and ring nebulae surrounding mass…

astro-ph.GA2019★ 1 cited

Galactic abundance gradients from deep spectra of HII regions

C. Esteban, J. García-Rojas, K. Z. Arellano-Córdova +1

We present some results of an ongoing project devoted to reassess the radial abundance gradients in the disc of the MilkyWay based on deep spectroscopy of Hii regions. The data hav…