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arXiv · 2405.12361

The influence of ionized gas kinematics on HII galaxies. The cases of Tol 1004-296 and Tol 0957-278

Henri Plana·Vitor G. Alves·Maiara S. Carvalho
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Abstract

Blue Compact Galaxies (BCGs), also known as \HII\ galaxies, are dwarf, star-forming objects with relatively simple dynamics, which allows for the investigation of star formation mechanisms in a cleaner manner compared to late-type objects. In this study, we have examined various characteristics of the interstellar medium, in connection with the kinematics and dynamics of ionized gas, in Tol 1004-296 and Tol 0957-278. These two objects were observed using the SOAR Integral Field Spectrometer (SIFS) attached to the Southern Observatory for Astrophysical Research (SOAR). Both galaxies were observed with two gratings: one with medium resolution for monochromatic and abundance maps, and another with high resolution for kinematics and profile analysis. Additionally, we conducted an analysis on the velocity and velocity dispersion maps using intensity-velocity dispersion (I - $\sigma$) and velocity-velocity dispersion (Vr - $\sigma$) diagrams. Neither object exhibits a rotation pattern, and only Tol 1004-296 shows a velocity gradient between the two principal knots. However, the study reveals the significant role played by velocity dispersion in the star formation process. Specifically, we identified a relationship between monochromatic intensity, metallicity, and velocity dispersion, where high emission corresponds to low metallicity and low velocity dispersion. Tol 1004-296, in particular, exhibits a distinctive linear high velocity dispersion pattern between the two main knots, suggesting that both star formation sites are pushing the gas in opposite directions.

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Henri Plana, Vitor G. Alves, Maiara S. Carvalho. 2024-05-20. The influence of ionized gas kinematics on HII galaxies. The cases of Tol 1004-296 and Tol 0957-278. https://arxiv.org/abs/2405.12361

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