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J. D. P. Kenney (Yale U.), G. F. Benedict (U. Texas), D. Friedli (Geneva Obs.)
Multi-color HST WFPC2 images of the double-barred spiral galaxy NGC~4314 show young blue stellar spiral arms emerging from a circumnuclear ring of star formation. These arms do not connect with the spiral arms of the outer disk, but are a distinct circumnuclear feature. They are not associated with the dust lanes, molecular gas, or HII regions which all exist in the center of this galaxy, but are an independent spiral-shaped enhancement in the density of young stars. The broadband colors of these stars indicate an age of ~108 yrs. We describe numerical simulations and theory which suggest that the blue stellar arms arise from stars which form in the ring, and are subsequently driven radially outwards by the gravitational torques exerted by the nuclear bar located just inside the ring. This dynamical redistribution of circumnuclear stars by a nuclear bar forms a thin annular disk of young stars ~300-700 pc in radial extent. The spiral arms represent a significant redistribution of angular momentum within the central kpc of this spiral galaxy.