Time‐Distance Sunspot Seismology with GONG Data

We present time-distance analyses of several active regions and a region of quiet Sun observed with the Global Oscillation Network Group (GONG). Analyzing temporal correlations between the p-mode oscillation signal observed within the sunspots with the signals integrated within surrounding annuli, we conrm the recent nding of Duvall and his colleagues that travel times (q`) for outward propagating p-modes are smaller by approximately 1 minute than corresponding inward travel times (q~). We also analyze correlations of the oscillation signal integrated within annuli of di erent radii. By varying the radius of the inner annulus (that which is closer to the target) we show that the radial extent of the region giving rise to the travel time perturbations is coincident with the outer boundary of the sunspot penumbrae.

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