Oscillations and running waves observed in sunspots

In order to study umbral oscillations, running penumbral waves and the rela tionship between them, we analyzed CCD, high resolution, sunspot observatio ns obtained at center and the wings of the H alpha line and the Fe I 5576 A ngstrom line. The UBF filter was used in order to produce high cadence sequ ences of filtergrams. Images were processed to remove the sharp intensity g radient between the umbra and the penumbra. They show the waves to start ou t around umbral oscillating elements and to propagate outwards forming conc entric cycles around the elements. The waves appear to propagate beyond the outer edge of the photospheric penumbra, in the superpenumbra, where they dilute. Comparing images in 9 wavelengths along the H alpha profile we foun d out that the waves are definitely better observed near the H alpha center and near the blue wing -0.35 Angstrom. This indicates a possible vertical upward mass motion in the oscillating penumbral structure and that the osci llation is not symmetric about zero. We found different oscillating modes. Standing umbral oscillations are domi nant in the umbra and inner penumbra; their frequency is around 6.5 mHz. Si milar oscillations are observed in the penumbra - superpenumbra boundary bu t with considerably lower frequency (2 mHz). Oscillations are absent or hav e reduced magnitude in the central part of the penumbra. Penumbral waves ar e running waves propagating with a constant phase velocity around 13 km s(- 1); their frequency is remaining constant over the whole penumbra, in the b and of 3 mHz. We produced "time slice images" which show, that there is not a clear relationship between umbral oscillations and running penumbral wav es.