Tadafumi Matsuno, SOKENDAI 4th year (D2)(Supervisor: Wako Aoki,Yutaka Komiyama,Takuji Tsujimoto)
The first chemo-dynamical view of very metal-poor stars
The second data release of Gaia (Gaia DR2) enables us to explore motions of a large number of stars in the Milky Way. Maximum scientific output would be obtained by complimenting the Gaia data set with stellar chemical abundances, since stellar motions tell us about past dynamical interactions between Milky Way and satellite galaxies whereas chemical abundances tell us about past star formation activities. To understand the formation history of the Galactic stellar halo, one of the oldest structures in the Milky Way, we have crossmatched the SAGA database, which complies results of abundance measurements for very metal-poor stars in literatures, to the Gaia DR2 catalog. In this talk, after describing the procedure of the crossmatch, I will introduce the latest results from the first chemo-dynamical analysis of very metal-poor stars.
Satoshi Kikuta, SOKENDAI 4th year (D2)(Supervisor: Masa Imanishi,Yuichi Matsuda,Yutaka Komiyama)
Lyman alpha imaging around a hyperluminous QSO at z=2.84 with HSC
We present the results of our Lyα imaging around a hyperluminous QSO, HS1549+1919, at z=2.84 with Hyper Suprime-Cam (HSC). Thanks to the HSC’s overwhelmingly large FoV, we detected >3000 Lyα emitters (LAEs) in diverse environments within a 1.1 deg^2 FoV. The QSO is confirmed to reside in the very center of a protocluster and is surrounded by a ~1pMpc-scale diffuse Lyα nebula. The EW distribution and properties of Lyα halos are studied as a function of environments. At the center, extreme objects such as QSOs, LABs, and SMGs are far more abundant than fields, suggesting a large amount of gas is accreting towards the center.