Ionization state and geometry of the extragalactic HII region SMC-N88A for the interpretation of observations of galaxies in the epoch of reionization

DIAZ, C. G.; MAST, D.; OIO, G.; BASSETT, R.

Boletín de la Asociación Argentina de Astronomía

Asociación Argentina de Astronomia

Lugar: Capital; Año: 2023 vol. 64 p. 127 - 129

0571-3285

Ionizing photons from the first galaxies contributed to the progressive re-ionization of the intergalactic hydrogen, which ended by z = 6. One of the main unknowns of this process is the fraction of ionizing photons that escape from galaxies and reach the intergalactic medium during this epoch. However, no telescope can directly detect this radiation on objects at z >6 because it is absorbed by the neutral hydrogen of the intergalactic medium in the same cosmic reionization process. For this reason, several alternative indicators of the escape of ionizing photons have been proposed, based on both emission and absorption lines. In this work, the long-term goal is to test the models used in the interpretation of observations of nebular emission lines from galaxies at very high redshift. We have observed two compact H ii regions of the Small Magellanic Cloud with the Integral Field Unit (or IFU) of GMOS-S, to study the physics involved in the escape of ionizing photons produced by massive stars inhabiting young H ii regions. At a distance of 61 kpc, the proximity of these objects makes it possible to study the geometry and kinematics of the gas in emission with a spatial resolution unattainable in galaxies of the reionization epoch. In this opportunity, we present the bases of the project and the data obtained for SMC-N88A