2025/12/16 by Esteban, C., Vilchez, J. M., García-Rojas, J. +15
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Electrical and Electromagnetic Research #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Instrumentation and Methods for Astrophysics (astro-ph.IM)
paper · doi:10.48550/arxiv.2512.14790
openalex publication_date 2025/12/16 · openalex created_date 2025/12/19 · openalex updated_date 2026/07/28
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). Currently available telescopes cannot adequately detect and measure heavy element recombination lines and certain faint collisionally excited lines, which are essential for exploring the effects and biases that potential inhomogeneities in electron temperature and density of the ionized gas may have on determining the chemical composition of these galaxies. On the other hand, the origin of very high-ionization lines (e.g. He II, [Ne V], C IV]) measured in the spectra of an important fraction of these objects remains unknown and a challenge to current stellar models, suggesting the presence of Population III-like stars and/or the existence of non-conventional ionizing sources. Obtaining very deep spectra for a selected sample of local star-forming dwarf galaxies would provide unprecedented constraints on their nature, ionization and true chemical abundances, and could change the metallicity scale we assume to understand the chemical evolution of galaxies over cosmic time.