Anjali John K D3, SOKENDAI, Mitaka（supervisor : Suematsu Yoshinori）
Temporal evolution of the Sun’s Polar Magnetic Patches as observed with Hinode
The Sun’s polar region is covered by countless discrete flux elements called as magnetic patches. The magnetic patches are believed to be formed from the remnant magnetic flux from the active latitudes which is transported to the polar region through diffusion and meridional circulation. It is likely that large unipolar patches with magnetic flux >10^18 Mx determine the magnetic polarity of each poles and their total flux is modulated by the solar cycle. It is important to understand the temporal evolution of these large patches to derive information of magnetic activities in the polar region, especially, the mechanism of magnetic polarity reversal. We also like to investigate the interaction between magnetic patches and the polar faculae whose occurrence tends to be associated with the large magnetic patches, according to our previous study. We obtained Hinode/SP and FG data for six hours of the south polar region in March 2013. We will show results obtained from this analysis.
Ayumu Matsuzawa D1, SOKENDAI, Mitaka（supervisor : Satoru Iguchi）
Absorbing spectrum in galactic nucleus of M87 from VLBA archive data
Super Massive Black Hole (SMBH) in Active Galactic Nuclei (AGN) attracts matters to form an accretion disk by its strong gravity. AGN is very bright than normal galaxy due to huge luminosity of accretion disk. In order to emit the huge luminosity, that requires a lot of accretion matter accreting to SMBH. The absorption was seen in spectrum of VLBI observation near SMBH. There are the two possibilities that absorption as synchrotron-self-absorption (SSA) from optically thin region of AGN jet or free-free-absorption (FFA) from cold dense plasma around SMBH. This cold dense plasma (we called FFA plasma) was considered as accreting matter to SMBH. The analysis of FFA around SMBH has been used to investigate this kind of accretion process at very vicinity (~pc-scale) of the BH. The purpose of my research is probing the FFA plasma around SMBH of M87. M87 is one of very important object, because M87 has the second-largest apparent Schwarzschild radius next to SrgA*.In order to probe the FFA plasma around SMBH of M87, we required the absorption spectrum of VLBI observation near SMBH of M87.We make the SED with seven frequencies (0.324, 1.6, 2.2, 4.9, 8.4, 15, 22GHz) on SMBH of M87 from VLBA archive data to confirm the absorption spectrum and the SED shown absorption spectrum.