A population synthesis study of the galaxy NGC5018

We have carried out long-slit spectral observations of NGC5018 in the range λλ3600 – 7500 Å using the BAO 2.16 m telescope. By means of a population synthesis based on a star cluster spectral sample, we have studied the galaxyʹs interior stellar populations and star formation history. We present the inferred proportions of its various populations with different ages and metal abundances. The results indicate that in NGC5018 there exist not only a great many old stellar components with low metal abundance, but also some younger stellar populations (T = 5 × 108yr) that also contribute importantly to the galaxyʹs luminosity. The physical cause for the formation of these younger stellar populations may be tidal interactions and minor mergers with other galaxies. And the history of star formation in elliptical galaxies has probably undergone two or more burst episodes. The results can explain well the observed characteristics of NGC5018, such as its somewhat bluer color and weaker spectral index Mg2.