Oscillations and running waves observed in sunspots II. Photospheric waves

To continue our study of waves related to sunspots in the photosphere, we a nalyzed CCD, high resolution sunspot observations obtained in the Fe I 557. 6 nm line. We produced "time slice images" which reveal inward slow propaga ting waves in the photospheric penumbra and outward propagating waves in th e area around the sunspot. The phase velocity of the waves is near 0.5 km s (-1) in both cases and their horizontal wavelength about 2500 km. The waves could be related either to solar p-modes or to the subphotospheric layer l arge-scale convection.