Population Synthesis for the Spectrum of NGC5018

The long-slit spectral observations of NGC5018 in the range 3600-7500 A with the BAO 2.16m telescope are presented. Using the population synthesis method based on star cluster, the nuclear stellar population and star formation history of NGC5018 are analyzed. The results indicate that the continuum flux fraction at 5870 A owing to an old component is ~ 64%, and that of very young components (T108yr)is1%, respectively. A very interesting result is there exist lots of T=5x108yr young stellar populations in this old elliptical galaxy. It is supposed that the cause of the star formation is the influence of tidal interactions and minor mergers with other galaxies. The star formation history of the elliptical galaxies maybe very complex, but the results can give the observation characters of NGC5018 a good explanation.