THEMIS Solar Telescope

THEMIS observations of the east sunspot group of the active region NOAA 13981 on February 6th 2025. The left image is a Knox-Thompson reconstructed from red continuum broadband camera. The right panels are intensity maps reconstructed from spectral observations by the MTR2 spectrograph observing the Hα absorption line. Theses maps are reconstructed from a scan by the telescope of the active region. While these intensity images have a lower spatial resolution, they provide a wealth of spectroscopic information. The region was observed during a flare, as can be noted by the typical ribbon-shape emission in the Hα line centre. This emission is absent from the continuum emission, indicating a chromospheric emission phenomena. Meanwhile, the red wing maps (Hα+1Å and Hα+0.5Å) display dark absorbing material above the location of the flare ribbons, signature of down-flowing dense material, a phenomena nicknamed “coronal rain”.