The elliptical galaxy NGC 5044: Stellar population and ionized gas

Universidade Federal do Rio Grande do Sul (UFRGS), Instituto de Física, Departamento de Astronomia, Brasil e-mail: [maurogr;mgp]@if.ufrgs.br

Corresponding author: Ch. Bonatto, charles@if.ufrgs.br

Received: 10 September 2003
Accepted: 16 February 2004

Abstract

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 metal-line profiles along the galaxy which suggests an enhancement of α elements, particularly towards the central region. The stellar population synthesis showed that the component with dominates the  Å flux in the central region of NGC 5044, contributing with ~ of the total flux, while in the external regions the contribution decreases to ~. The component with contributes with ~ in the central region, and ~ in the external regions. The component with contributes with ~ in the central region, and ~ in the external regions. The three components have ~10¹⁰ years. 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 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.