High-z QSO survey at z ~ 6 and 7 with Suprime-Cam / The new black hole mass estimator: Paα

【日時】4月25日(水) 10:30~12:00
【場所】国立天文台・三鷹 中央棟(北)1階 講義室
【発表者1】Yoshifumi Ishizaki (総研大 D2・三鷹、指導教員 : Nobunari Kashikawa)
【タイトル】High-z QSO survey at z ~ 6 and 7 with Suprime-Cam
We are on going deep zB/zR imagings for 7 deg^2 in total of UKIDSS-DXS fields in order to detect high-z QSOs around z ∼ 7 down to J<23.5. This observation is a new search for the most distant QSOs around z = 6 and 7 utilizing the unique capabilities of wide-field imaging of Subaru/Suprime-Cam, its high-sensitivity CCDs at 〜 1μm, and special filters to effectively isolate high-z QSOs from M/L/T dwarfs. I will speak about the unique way of observation mainly. 【発表者2】Keisuke Imase (総研大 D2・三鷹、指導教員 : Masatoshi Imanishi) 【タイトル】The new black hole mass estimator: Paα アブストラクト Active Galactic Nuclei (AGNs) are luminous objects, found in the centre of galaxies. It is believed that they have supermassive black hole and accretion disk in their central region, surrounded with broad-line region(BLR). This picture is called "Unified model for AGN" (e.g., Antonucci 1993) Today, the correlation between masses of black holes of AGNs (MBHs) and the properties of their host galaxies has been found (so-called "co-evolution"). Therefore, it is very important to estimate MBHs of more AGNs in more accurate way. MBHs are mainly estimated with broad optical and UV emission lines (Hβ, MgII), using their line width and flux. More than half of AGNs, however, are affected with the foreground gas and dust. For such AGNs (so-called "dusty AGNs"), it is difficult to use UV/optical lines as estimators of MBHs. On the other hand, Paα line, the strongest line in near-infrared(NIR) and free of blending, are detectable in "dusty AGNs" and ultra luminous IR galaxy(ULIRG). We have observed 21 nearby PG QSOs with IRTF/SpeX in order to establish Paα lines as a new estimator of MBHs for dusty AGNs. In the colloquium, we report the present results and our future work.