[P-EM16] Heliosphere and Interplanetary Space

[PEM16-07] Solar microwave spectra observation by the Yokosuka Radio Polarimeter (YoRP)

*Kyoko Watanabe¹, Ryoka Shirogauchi¹, Kensho Yasui¹, Shinnosuke Kitajima¹, Ryosuke Okubo¹, Masumi Shimojo², Kazumasa Iwai³, Satoshi Masuda³ (1.National Defense Academy of Japan, 2.National Astronomical Observatory of Japan, 3.ISEE, Nagoya University)

Keywords:Solar microwave emission, Radio Polarimeter, Sunspot, Solar Flare

Solar microwave observation has been performed at Toyokawa and Nobeyama for more than 70 years (Shimojo and Iwai, 2023). Solar microwave is known to correlate well with the extreme ultraviolet (EUV) emission from the Sun, which has a significant impact on space weather conditions, and is still used to monitor the conditions of space weather.
On the other hand, observations by the Nobeyama Radio Polarimeters (NoRP) will end the end of JFY 2027. In addition to continuous observation of solar microwave, equipment to acquire the dynamic spectrum of solar microwave emissions, which had been able to observe only limited frequencies with the NoRP, was installed at the National Defense Academy of Japan in March 2024 (the Yokosuka Radio Polarimeter; YoRP). Sun tracking observations became possible in October 2024, and are now in order to perform calibration with NoRP data, data acquisition for calibration is performed manually once a day.
In this study, first, microwave spectra observed by the YoRP from around mid-October 2024 to during January 2025 are calibrated using NoRP daily fluxes. This allowed us to derive the variation of the microwave spectra due to sunspot variations. We are also able to observe the microwave emission spectrum of the C9.1 class flare that occurred at 1:56 UT on 23 January 2015. In this paper, we report on these observation results and the latest status of the YoRP.