The elliptical galaxy NGC 5044: Stellar population and ionized gas

In this work we investigate the stellar population, metallicity distribution and ionized gas in the elliptical galaxy NGC 5044, using long-slit spectroscopy and a stellar population synthesis method. We found differences in the slope of FeI and Mg2 lines gradients, which suggests an enhancement of α elements, particularly towards the central region. The stellar population synthesis shows that the contribution, at λ5870, of the most metallic and old stellar population (Z/Z_⊙ ∼ 0.0 and 1010 year) is dominant in NGC 5044. The presence of a non-thermal ionization source, such as a low-luminosity AGN and/or shock ionization, is implied by the large values of the ratio [NII]/Hα observed in all sampled regions. However, the emission lines observed in the external regions indicate the presence of an additional ionization source, probably hot, post-AGB stars.