Metallicity determination in gas-rich galaxies with semiempirical methods

A study of the precision of the semiempirical methods used in the determination of the chemical abundances in gas-rich galaxies is carried out. In order to do this, the oxygen abundances of a total of 438 galaxies were determined using the electronic temperature, the R 23, and the P methods. The new calibration of the P method gives the smaller dispersion for the low- and high-metallicity regions, while the best numbers in the turnaround region are given by the R 23 method. We also found that the dispersion correlates with the metallicity. Finally, it can be said that all of the semiempirical methods studied here are quite insensitive to metallicity with a value of 8.0 ± 0.2 dex for more than 50% of the total sample.