Subsurface Acoustic Images of Solar Active Regions in Different Frequencies with TON Data

[[abstract]]We apply the method of `acoustic imaging' to construct subsurface acoustic images of solar active regions using p-mode signals in different frequency ranges with TON data. Acoustic imaging, based on a time-distance relationship, coherently collects observed acoustic signals at the surface to reconstruct acoustic signals in the solar interior. Earlier studies have shown that this method successfully reveals acoustic signatures of solar magnetic regions, both in the sense of intensity and phase shift. We now first separate observed p-mode signals into frequency ranges centered at 3, 4, 5, and 6 mHz with a band width of 1 mHz, and use them separately to construct subsurface acoustic images. Among others, our results show that acoustic absorptions in solar active regions are stronger at the 3- and 4-mHz bands than at the 5- and 6-mHz ones. Its dependence on the degree l is very weak. Our images also indicate that there are phase-shift differences among solar acoustic signals with different frequencies in their propagation.[[fileno]]2010104030007[[department]]物理