Observations of Sunspot Oscillations in G band and Ca II H line with Solar Optical Telescope on Hinode

Abstract

Exploiting high-resolution observations made by the Solar Optical Telescope onboard Hinode, we investigate the spatial distribution of power spectral density of oscillatory signal in and around NOAA active region 10935. The G-band data show that in the umbra the oscillatory power is suppressed in all frequency ranges. On the other hand, in Ca II H intensity maps oscillations in the umbra, so-called umbral flashes, are clearly seen with the power peaking around 5.5 mHz. The Ca II H power distribution shows the enhanced elements with the spatial scale of the umbral flashes over most of the umbra but there is a region with suppressed power at the center of the umbra. The origin and property of this node-like feature remain unexplained.

7 pages, 8 figures, accepted for publication in PASJ (Hinode Special Issue)

References in corpus (3)

• Spectropolarimetric investigation of the propagation of magnetoacoustic waves and shock formation in sunspot atmospheres
• Solar Atmospheric Oscillations and the Chromospheric Magnetic Topology
• Initial Helioseismic Observations by Hinode/SOT

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