Analysis of the Internal Radial Gradient of Chemical Abundances in Spiral Galaxies from CALIFA by A. F. S. Cardoso, O. Cavichia, M. Mollá, L. Sánchez-Menguiano

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Uncovering the Hidden Physical Structures and Protostellar Activities in the Low-metallicity S284-RE Region: Results from ALMA and JWST by O. R. Jadhav, L. K. Dewangan, Aayushi Verma, N. K. Bhadari, A. K. Maity, Saurabh Sharma, Mamta

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The Sunburst Arc with JWST. III. An Abundance of Direct Chemical Abundances by Brian Welch, T. Emil Rivera-Thorsen, Jane R. Rigby, Taylor A. Hutchison, Grace M. Olivier, Danielle A. Berg, Keren Sharon, Håkon Dahle, M. Riley Owens, Matthew B. Bayliss, Gourav Khullar, John Chisholm, Matthew Hayes, Keunho J. Kim

“…Abundances of sulfur, argon, neon, and iron are consistent with local low-metallicity H ii regions and low-redshift galaxies. This study represents the most complete chemical abundance analysis of an individual H ii region at Cosmic Noon to date, which enables direct comparisons between local H ii regions and those in the distant Universe.…”
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Discovery of Metal-poor and Distant Pre–Main Sequence Candidates in WLM with JWST by Venu M. Kalari, Ricardo Salinas, Morten Andersen, Guido De Marchi, Monica Rubio, Jorick S. Vink, Hans Zinnecker

“…They are concentrated within a cluster roughly 10 pc (2″) across, situated in the H ii region [HM95]-9. These are the most distant and metal-poor PMS stars known, and they can offer new quantitative insights into star formation at low metallicities.…”
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A Wideband Chemical Survey of Massive Star-forming Regions at Subarcsecond Resolution with the Submillimeter Array by Charles J. Law, Qizhou Zhang, Arielle C. Frommer, Karin I. Öberg, Roberto Galván-Madrid, Eric Keto, Hauyu Baobab Liu, Paul T. P. Ho, Andrés F. Izquierdo, L. Ilsedore Cleeves

“…The chemical richness of our sample is consistent with an evolutionary sequence from the line-rich hot cores and hypercompact H ii regions of G28.20-0.05 and G20.08-0.14 N to the more chemically modest ultracompact H ii regions in G35.58-0.03, followed by the molecule-poor H ii region W33 Main. …”
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The Integral Field View of the Orion Nebula by Adal Mesa-Delgado

“…The analysis of these morphologies using IFS has given us new insights into the abundance discrepancy problem, a long-standing and unresolved issue that casts doubt on the reliability of current methods used for the determination of metallicities in the universe from the analysis of H II regions. Results imply that high-density clumps and high-velocity flows may play an active role in the production of such discrepancies. …”
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The Main Ionization Sources of Gas in Several Nearby Star Forming Galaxies by Behjat Zarei Jalalabadi, Abbas Abedi, Alexei Moiseev

“…The shock excitation in the diffuse ionized gas (DIG) can be realized by the correlation between ρ and σ, while the H II regions with low level turbulent motions can be characterized by the absence of this correlation. …”
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HCG 57: Evidence for Shock-heated Intergalactic Gas from X-Rays and Optical Emission Line Spectroscopy by Ewan O’Sullivan, P. N. Appleton, B. A. Joshi, Lauranne Lanz, Katherine Alatalo, Jan M. Vrtilek, Andreas Zezas, Laurence P. David

“…The optical emission lines in the central regions of HCG 57D show excitation properties consistent with H  ii -regions, while the outer rim of HCG 57D parts of the bridge and the outer regions of HCG 57A show evidence of shocked gas consistent with shock velocities of 200–300 km s ^−1 . …”
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Diffuse Ionized Gas in the Anticenter of the Milky Way by Shiming Wen, Wei Zhang, Lin Ma, Yunning Zhao, Man I. Lam, Chaojian Wu, Juanjuan Ren, Jianjun Chen, Yuzhong Wu, Guozhen Hu, Yonghui Hou, Yongheng Zhao, Hong Wu

“…Using data from the Large Area Multi-Object fiber Spectroscopic Telescope Medium-Resolution Spectroscopic Survey of Nebulae, we create a sample of 17,821 diffuse ionized gas spectra in the anticenter region of the Milky Way by excluding fibers in the directions of H ii regions and supernova remnants. We then analyze the radial and vertical distributions of three line ratios ([N ii ]/H α , [S ii ]/H α , and [S ii ]/[N ii ]), as well as the oxygen abundance. …”
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