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Related papers: Analytical strong line diagnostics and their redsh…

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We introduce genesis-metallicity, a gas-phase metallicity measurement python software employing the direct and strong-line methods depending on the available oxygen lines. The non-parametric strong-line estimator is calibrated based on a…

Astrophysics of Galaxies · Physics 2026-01-12 Danial Langeroodi , Jens Hjorth

Gas metallicity, ionization parameter, and gas pressure can affect the observed ratios of specific strong emission lines within galaxies. While the theoretical strong lines diagnostics for gas metallicity, ionization parameters, and gas…

Astrophysics of Galaxies · Physics 2024-11-07 Peixin Zhu , Lisa J. Kewley , Ralph Sutherland

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…

Astrophysics of Galaxies · Physics 2025-11-26 Ziming Peng , Renbin Yan , Xihan Ji , Zesen Lin , Man-Yin Leo Lee

Recent observations by James Webb Space Telescope discovered a number of high-redshift galaxies with strong emission lines from doubly ionized oxygen. Combined with ALMA observations of far-infrared lines, multi-line diagnostics can be…

Astrophysics of Galaxies · Physics 2023-06-30 Yurina Nakazato , Naoki Yoshida , Daniel Ceverino

We present a sample of low-redshift (z<0.133) candidates for extremely low-metallicity star-forming galaxies with oxygen abundances 12+logO/H<7.4 selected from the Data Release 14 (DR14) of the Sloan Digital Sky Survey (SDSS). Three methods…

Astrophysics of Galaxies · Physics 2019-03-06 Y. I. Izotov , N. G. Guseva , K. J. Fricke , C. Henkel

Aims: We generate theoretical ultraviolet and extreme-ultraviolet emission line ratios for O IV and show their strong versatility as electron temperature and density diagnostics for astrophysical plasmas. Methods: Recent fully relativistic…

Solar and Stellar Astrophysics · Physics 2009-11-13 F P Keenan , P J Crockett , K M Aggarwal , D B Jess , M Mathioudakis

Recent work has demonstrated that widely used strong-line oxygen abundance indicators, such as O3N2, $\rm R23$, and $\widehat{\rm R}$, suffer from large uncertainties when applied to high-redshift galaxies. We show that this loss of…

Astrophysics of Galaxies · Physics 2026-01-29 Shihong Liu , Yu Rong , Tie Li , Yao Yao , Cheng Jia , Enci Wang , Hongxin Zhang , Zhicheng He , Huiyuan Wang , Xu Kong

Emission line diagnostic diagrams probing the ionization sources in galaxies, such as the Baldwin-Phillips-Terlevich (BPT) diagram, have been used extensively to distinguish AGN from purely star-forming galaxies. Yet, they remain poorly…

This Letter presents a new, remarkably simple diagnostic specifically designed to derive chemical abundances for high redshift galaxies. It uses only the H \alpha, [N II] and [S II] emission lines, which can usually be observed in a single…

Astrophysics of Galaxies · Physics 2016-02-03 Michael A. Dopita , Lisa J. Kewley , Ralph S. Sutherland , David C. Nicholls

We explore spectroscopic and photometric methods for identifying high-redshift galaxies containing an Active Galactic Nucleus (AGN) with JWST observations. After demonstrating the limitations of standard optical methods, which appear…

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…

Astrophysics of Galaxies · Physics 2025-08-28 Song-lin Li , Trevor J. Mendel , Mark R. Krumholz , Emily Wisnioski

The N2 index ([N II]6584/Ha) is used to determine emission line galaxy metallicities at all redshifts, including high redshift, where galaxies tend to be metal-poor. The initial aim of the work was to improve the calibrations used to infer…

Astrophysics of Galaxies · Physics 2015-06-23 A. B. Morales-Luis , E. Perez-Montero , J. Sanchez Almeida , C. Munoz Tunon

The flux ratios of high-ionization lines are commonly assumed to indicate the metallicity of the broad emission line region in luminous quasars. When accounting for the variation in their kinematic profiles, we show that the NV/CIV,…

Astrophysics of Galaxies · Physics 2021-06-21 Matthew J. Temple , Gary J. Ferland , Amy L. Rankine , Marios Chatzikos , Paul C. Hewett

The radial gradient of gas-phase metallicity is a powerful probe of the chemical and structural evolution of star-forming galaxies, closely tied to disk formation and gas kinematics in the early universe. We present spatially resolved…

We analyze optical (UV rest-frame) spectra of X-ray selected narrow-line QSOs at redshift 1.5 < z < 3.7 found in the Chandra Deep Field South and of narrow-line radio galaxies at redshift 1.2 < z < 3.8 to investigate the gas metallicity of…

Astrophysics · Physics 2009-11-11 Tohru Nagao , Roberto Maiolino , Alessandro Marconi

We present a measurement of the mass-metallicity relation (MZR) at cosmic noon, using the JWST near-infrared wide-field slitless spectroscopy obtained by the GLASS-JWST Early Release Science program. By combining the power of JWST and the…

(abridged) We present deep spectroscopy of a large sample of low-metallicity emission-line galaxies. The main goal of this study is to derive element abundances in these low-metallicity galaxies. We analyze 121 VLT spectra of HII regions in…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-08 N. G. Guseva , Y. I. Izotov , G. Stasinska , K. J. Fricke , C. Henkel , P. Papaderos

We infer stellar metallicity and abundance ratio gradients for a sample of red galaxies in the Sloan Digital Sky Survey (SDSS) Main galaxy sample. Because this sample does not have multiple spectra at various radii in a single galaxy, we…

Astrophysics of Galaxies · Physics 2015-08-06 Benjamin Roig , Michael R. Blanton , Renbin Yan

We determine the spectroscopic properties of ~1000 ostensibly star-forming galaxies at redshifts (z=4-10) using prism spectroscopy from JWST/NIRSpec. With rest-wavelength coverage between Lya and [S II] in the optical, we stack spectra as a…