射电天文研究组知识库

We present a study of decimetric radio activity using the first high time cadence (0.5 s) images from the Giant Meterwave Radio Telescope (GMRT) at 610 MHz associated with GOES C1.4- and M1.0-class solar flares and a coronal mass ejection (CME) onset that occurred on 2015 June 20. The high spatial resolution images from GMRT show a strong radio source during the C1.4 flare located similar to 500 '' away from the flaring site with no corresponding bright footpoints or coronal features nearby. In contrast, however, strong radio sources are found near the flaring site during the M1.0 flare and around the CME onset time. Weak radio sources located near the flaring site are also found during the maximum of the C1.4 flare activity that show a temporal association with metric Type III bursts identified by the Solar Broadband Radio Spectrometer at Yunnan Astronomical Observatory. Based on a multiwavelength analysis and magnetic potential field source surface extrapolations, we suggest that the source electrons of GMRT radio sources and metric Type III bursts originated from a common electron acceleration site. We also show that the strong GMRT radio source is generated by a coherent emission process, and its apparent location far from the flaring site is possibly due to the wave-ducting effect.