2025/09/01 by Magdalena J. Hamel-Bravo, David B. Fisher, Hamel-Bravo, Magdalena J. +15
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena
paper · pdf · doi:10.48550/arxiv.2509.01282
openalex publication_date 2025/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this work, we test the validity of Te - Te relations in resolved (10-200~pc) measurements of four nearby, low-metallicity (7.25 ≤ 12+log(O/H) ≤ 8.33), low-mass (106.78 ≤ M_*/M_\odot ≤ 108.7), starburst (10-4.5 ≤ sSFR ≤ 10-0.3) galaxies. We obtain VLT/X-Shooter spectra of NGC~5253, NGC~0625, SBS~0335-052E and IC~2828, targeting regions within these galaxies with bright point-like sources and diffuse gas. Our observations are designed to extend from the galaxy midplane into extraplanar gas likely belonging to galactic winds. We measure electron temperatures from five different auroral lines: [NII]~λ5755, [OII]~λλ7319,30, [SII]~λλ4069,76, [SIII]~λ6312, and [OIII]~λ4363. We compare the resulting Te - Te relations with previous studies of HII regions in nearby spiral galaxies. Our results show that Te - Te relations in low-metallicity starburst galaxies do not significantly deviate from Te - Te relations in HII regions of local spiral galaxies. We do not find significant differences in the diffuse, extraplanar gas. These results suggest that auroral lines provide a reliable metallicity diagnostic not only for high-redshift galaxies but also for the extended diffuse gas in extreme environments like outflows.