[Speaker 1]
Takatoshi Shibuya
[Title]
Surveys for Lyman Alpha Blobs at z=2 and 3
[Abstract]
LyA blobs (LABs) are mysterious extended sources at z ~ 2-6. Because LABs are thought to closely relate to the formation of / the feedback from massive galaxies, investigating the origin of their brightness and spatial extent is quite important. However, despite intensive observational and theoretical approaches, the formation mechanisms of LABs have been poorly constrained. In order to understand their hidden total energy budget and relationship with other galaxy populations, such as compact Lyman Alpha Emitters (LAEs) or massive Sub-Millimeter Galaxies (SMGs) selected by using various wavebands, surveys for LABs in well-observed fields in multi-wavelengths are crucially required.
For this purpose, we have undertaken narrow-band imaging surveys in 2 MUSYC fields, the Extended Chandra Deep Field-South and the Extended Hubble Deep field-South, for LABs at z=2.1 and 3.1. In this presentation, I will provide our preliminary results.
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[Speaker 2]
Jungmi Kwon
[Title]
Infrared Linear and Circular Polarimetry of the NGC 6334 Star Forming Region
[Abstract]
Magnetic fields have been thought to play a crucial role in regulating accretion onto protostars, both in powering and shaping outflows and removing angular momentum from disk material, to allow the protostar to gain mass. However, the precise role of the magnetic field is poorly understood and evidence for its shape and structure has not been forthcoming. Getting evidence for the morphology of these fields has been tricky though – and this is an area in which polarimetry can help. In particular, circular polarization can provide evidence for changing grain/field alignment directions along the line-of-sight and hence the presence of twisting fields. However, the observational database of circular polarimetry in star forming regions is still very small. In this presentation, we present deep linear and circular polarization images of the NGC 6334 massive star-formation complex observed in the near-infrared bands.

[Speaker 1]
John K Anjali
[Title]
Preliminary study on the characteristics of polar faculae
[Abstract]
TBA
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[Speaker 2]
Takuya Suenaga
[Title]
Searching for Planetary Mass Objects in Taurus Molecular Cloud
[Abstract]
A large number of substellar-mass objects isolated in star forming regions are now known, with masses ranging from those of brown dwarfs (BDs) to Planetary Mass Objects (PMOs). However, it is not well known the frequency of these objects or how they are formed. We have conducted deep i’, z’ observations toward the Taurus molecular cloud.
Based on the color selection, we have first found PMO candidates in Taurus. After planning spectroscopic follow-up, if these are confirmed to be YSOs and low effective temperature, we can suggest that the Initial Mass Function in Taurus continues into the planetary mass.

【日時】5月16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（敬称略）】片岡章雅（総研大 D1・三鷹、指導教員 : 富阪幸治)
【タイトル】
Settling Process of Dust Aggregates in Protoplanetary disks with Porosity Evolution
アブストラクト
abstract: How micron-sized dust aggregates evolve to kilo-meter-sized planetesimals in protoplanetary disks is one of the most important problems of the planet formation. Some previous studies using BPCA and/or BCCA models have shown that porosity has strong effects on coagulation and settling of dust aggregates. However, effects of the porosity evolution have not been taken into account before. We simulate coagulation of dust aggregates settling to an equatorial plane in a protoplanetary disk, using QBCCA model, in which the porosity evolution depends on the volume ratio of colliding two aggregates. We show that porous aggregates grow slowly and settle in longer timescale compared to compact grains. We also calculate wavelength-dependent optical depth and find that the 10 $\micron$ silicate feature remains in the case of porous aggregates even after they grow in the disk. Moreover, we find that compaction of dust aggregates affects optical depth in (sub)mm wavelength, which would be detected by ALMA.

【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
アブストラクト
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.

【日時】4月18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（敬称略）】（総研大 D2 坂井 伸行・三鷹、指導教員：本間 希樹
【タイトル】
Galactic Outer Rotation Curve project with VERA
【アブストラクト】
I will talk mainly about two topics,
(1) Sakai et al. 2012 in accepted and
(2) Future prospects of our project.
The abstract of (1) is shown as below：
We report measurement of trigonometric parallax of IRAS 05168+3634 with VERA.
The parallax is 0.532 +/- 0.053 mas, corresponding to a distance of 1.88+0.21 －0.17 kpc. This result is significantly smaller than the previous distance estimate of 6 kpc based on kinematic distance. This drastic change in the source distance revises not only physical parameters of IRAS 05168+3634, but also its location of the source, placing it in the Perseus arm rather than the Outer arm. We also measure proper motions of the source. A combination of the distance and the proper motions with systemic velocity
yields rotation velocity (Θ) of 227+9－11 km s－1 at the source, assuming Θ0 = 240 km s－1. Our result combined with previous VLBI results for six sources in the Perseus arm indicates that the sources rotate systematically slower than the Galactic rotation velocity at the LSR. In fact, we show observed disk peculiar motions averaged over the seven sources in the Perseus arm as (Umean, Vmean) = (11 +/- 3, -17 +/- 3) km s－1, indicating that these seven sources are systematically moving toward the Galactic center, and lag behind the Galactic rotation.