2003A&A...410..803B

We investigate the stellar population content in the lenticular galaxies NGC 1023, NGC 3115 and NGC 4203 applying a population synthesis method based on a seven component spectral basis with different ages - 2.5x10⁶, 10x10⁶, 25x10⁶, 75x10⁶, 200x10⁶, 1.2x10⁹ and older than 10¹⁰years, and metallicity in the range -1.3≤[Z/Z_☉]≤-0.2. This study employs two-dimensional STIS spectra in the range λλ2900-5700Å, obtained from the Hubble Space Telescope public archives. We extracted one-dimensional spectra in adjacent windows 100pc wide (projected distance) from the nuclear regions up to 300-400pc. The largest contribution, both in λ5870Å flux and mass fraction, comes from old stars (age>10¹⁰years). We verified the possible existence of circumnuclear bursts (CNBs) in NGC 3115 and NGC 4203.