Chemical abundances in 7 metal-poor HII regions and a determination of the primordial helium abundance

Understand

We conducted a long-slit spectrophotometry analysis to obtain the chemical abundances of seven metal-poor HII regions in three galaxies: UM 160, UM 420, and TOL 0513-393.

• The data have been taken with the Focal Reducer Low Dispersion Spectrograph 1 (FORS1) at the 8.2-m Very Large Telescope.
• We derived the physical conditions and the chemical abundances of N, O, Ne, S, Ar, and Cl.
• We also performed a detailed analysis that involves abundance determinations using the $t^2$ formalism.