Present status of the Taiwan Oscillation Network

Abstract

The Taiwan Oscillation Network (TON) is a ground-based network measuring solar intensity oscillations for the study of the internal structure of the Sun. So far, four telescopes have been installed at Teide Observatory (Tenerife), Huairou Solar Observing Station (near Beijing), Big Bear Solar Observatory (California), and Tashkent (Uzbekistan). The TON telescopes take K-line full-disk solar images of diameter 1000 pixels at a rate of one image per minute. The TON high-resolution data is specially suitable to study local helioseismology. Here, we present recent results of three topics on local helioseismology from TON data: (1) Inference of Subsurface Magnetic Field From Absorption Coefficients of p-modes in Active Regions, (2) Subsurface Structure of Emerging Flux Regions From Helioseismology, and (3) Flow Around Sunspots From Measurements of Frequency Shift.