The Nature of the Double Nuclei in the Barred S0 Galaxy IC676
  The lenticular galaxy IC 676 is a barred galaxy with double nuclei and active
star formation in the central region. In this work we present the long-slit
spectroscopy and archival multi-wavelength images to investigate the nature and
origin of the double nuclei in IC 676. Through photometric 1D brightness
profiles and 2D image decomposition, we show that this galaxy consists of a
stellar bar with the length of $\sim$ 2.5 kpc and two S\'ersic disks both of
which with S\'ersic index $\it n \sim$ 1.3. There is probably little or no
bulge component assembled in IC 676. The luminosities of the double nuclei are
primarily dominated by young stellar populations within the ages of 1-10 Myr.
The northern nucleus has stronger star formation activity than the southern
one. The surface densities of the star formation rate in the double nuclei are
similar to those in starburst galaxies or the circumnuclear star forming
regions in spiral galaxies. Each of the double nuclei in IC 676 likely consists
of young massive star clusters, which can be resolved as bright knots in the
HST high resolution image. Our results suggest that IC 676 likely has a complex
formation and evolutionary history. The secular processes driven by the stellar
bar and external accretion may dominate the formation and evolution of its
double nuclei. This indicates that the secular evolution involving the internal
and external drivers may have an important contribution for the evolution of
lenticular galaxies.
