Localizing short-period pulsations in hard X-rays and Gamma-rays during an X9.0 flare

Abstract: The feature of quasi-periodic pulsations (QPPs) is frequently observed in the light curve of solar and stellar flares. In this letter, we investigated the QPP at a shorter period in high-energy channels of HXRs and Ggamma-ray continuum during an X9.0 flare on October 3, 2024 (SOL2024-10-03T12:08). The X9.0 flare was simultaneously measured by the Hard X-ray Imager, the Konus-Wind, and the Spectrometer/Telescope for Imaging X-rays. The shorter period center at about 1 s was determined by the fast Fourier transform with a Bayesianbased Markov Chain Monte Carlo and the wavelet analysis method. The restructured images show that the HXR sources are mainly separated into two fragments, regarding as double footpoints. Moreover, the footpoints move significantly during the flare QPP. Our results suggest that the intermittent and impulsive energy releases during the powerful flare are mainly caused by the interaction of hot plasma loops that are rooted in double footpoints. Thus, the flare QPP at a shorter period of about 1 s in HXR and Gamma-ray continuum emissions can be well explained by the interacting loop model.