2013.12.2-12.8

12月4日（水） 9:30～11：00　　Galaxy Workshop Subaru　すばる棟2F TV会議室
Dec 4 Wed　　　Galaxy Workshop Subaru　　　TV Conf. Room, Subaru Bldg. 2F

12月4日（水）10:30～12：00　　総研大コロキウム　　　中央棟（北）1F 講義室
Dec 4 Wed　　　SOKENDAI Colloquium　　　Lecture Room, Main Bldg. (North) 1F

12月4日（水）14:00～15：30　　Galaxy Workshop Subaru　すばる棟2F TV会議室
Dec 4 Wed　　　Galaxy Workshop Subaru　　　TV Conf. Room, Subaru Bldg. 2F

12月4日（水）14:10～15：10　　 理論コロキウム　　 　 コスモス会館 会議室
Dec 4 Wed　　　DTA Colloquium　　　Conference Room, Cosmos Lodge

12月5日（木）15：00～16：00　　VLBIコロキウム　　中央棟（南）2FVLBIセミナー室
Dec 5 Thu　　　VLBI Colloquium　　　VLBI Seminar Room, Main Bldg. (South)

12月6日（金）16：00～17：00　　国立天文台談話会　　　大セミナー室
Dec 6 Fri　　　NAOJ Seminar　　　Large Seminar Room

詳細は以下をご覧下さい。

12月4日(水)

Campus

Mitaka & Hawaii

Seminar title

Galaxy Workshop Subaru (in English)

Seminar type

irregular

Date/Time

Mitaka: 04 Dec (Wed) 09:30–11:00
Hawaii: 03 Dec (Tue) 14:30–16:00

Place

Mitaka: Subaru Bld. 2F TV Conf. Room
Hawaii: 104B

Speaker

Pascal Oesch

Affiliation

UCO/Lick Observatory

Title

Galaxy Build-up at the Cosmic Dawn:
New Insights from Ultra-Deep HST and Spitzer Observations

Abstract

Thanks to ultra-deep observations with the WFC3/IR camera on HST the frontier of galaxies has recently been pushed out to z~9-12, only ~450 Myr from the Big Bang.
From several large HST programs such as the HUDF09, CANDELS, or CLASH, we were able to identify large samples of more than 200 galaxies at z~7-8, and we are now starting to build up the sample sizes of z~9-11 galaxy candidates. In particular, the recent HUDF12 campaign further increased the depth of the WFC3/IR dataset over the Hubble Ultra-Deep Field (HUDF), and enabled us to detect a sample of nine very faint z>8 galaxy candidates in the HUDF. Additionally, the newly completed CANDELS data over GOODS-North now revealed four relatively bright
z~9-10 sources, which are in tension with the previous UV LF determination from the GOODS-South field, indicating that star-formation in the early universe might have been very stochastic. Using all z>8 candidates in and around both GOODS fields, we infer that the cosmic star-formation rate density in galaxies with SFR>0.7Msol/yr decreases rapidly at z>8, dropping by an order of magnitude from z~8 to z~10. With complementing, ultra-deep Spitzer IRAC data, we are additionally able to infer the stellar mass densities out to z~8-10.
In this talk I will highlight recent progress in exploring the high redshift frontier and in understanding the growth of galaxies in the first two billion years. In particular, I will present current constraints on the cosmic star-formation rate density out to z~10, and I will demonstrate the power of combining deep HST and Spitzer data to directly track the star-formation and mass build-up of z>=4 galaxies.

12月4日(水)

Campus

Mitaka

Seminar Name

SOKENDAI colloquium

Regular/Irregular

Regular

Date

10:30-12:00, Dec 4, 2013

Place

Lecture Room

Speaker 1

Sukom Amnart

Affiliation

D3, SOKENDAI, Mitaka（supervisor : Saeko Hayashi）

Title

TBA

Abstract

TBA

Speaker 2

Sako Nobuharu

Affiliation

D3, SOKENDAI, Mitaka（supervisor : Tetsuya Watanabe）

Title

An energetics study of X-ray jets

Abstract

For plasma acceleration in X-ray jets, three mechanisms have been considered, based on the reconnection model of X-ray jets; The reconnection jet produced by magnetic tension, the evaporation flow produced by pressure gradient, and the twisted jet produced by magnetic pressure. There are some evidences of X-ray jets in active regions (ARs) produced by pressure gradient. On the other hands, there is no observational evidence of X-ray jets by the other forces. In order to distinguish the evaporation flow from the other types of jets, I have studied the energetics of the X-ray jets.
Using over 100 X-ray jets greater than 3×104 km in length in ARs, quiet regions (QRs), and coronal holes (CHs), I have find no large differences in the life time, the width of the jets, and the area of the footpoint flares in such regions. On the other hands, the plasma number density of the X-ray jets and flares in ARs is ten times larger than those in QRs and CHs. From a comparison of the energy flux of the jets with the energy flux from the reconnection sites, which is estimated from the footpoint flares, I have found that the some events are consistent with the prediction from the evaporation flow. The energy fluxes of the other events are larger than the energy flux from the reconnection site. The kinetic energy fluxes of these jets are larger than the thermal fluxes. In my presentation, I will discuss the details.

Organizer

Name : Ayumu Matsuzawa

Comment

TV conference system is available connecting from Nobeyama, Hawaii,Mizusawa, and Okayama

12月4日(水)

Campus

Mitaka & Hawaii

Seminar title

Galaxy Workshop Subaru (in English)

Seminar type

irregular

Date/Time

Mitaka: 04 Dec (Wed) 14:00–15:30
Hawaii: 03 Dec (Tue) 19:00–20:30

Place

Mitaka: Subaru Bld. 2F TV Conf. Room
Hawaii: 104B

Speaker

Gu Liyi

Affiliation

RESCEU, Univ. of Tokyo

Title

Towards a New Paradigm Based on Galaxy-ICM Interactions in Galaxy Clusters

Abstract

In galaxy clusters, hundreds of galaxies are confined within the deep gravitational potential, and moving with a virial speed. However, they are not traveling in vacuum; instead, they are swimming in a sea of magnetized, X-ray emitting hot plasma (ICM) which constitutes 80-90% of the detected baryons. We expect that galaxies interact strongly with the magnetized ICM, transfer their dynamical energies and metals to the ICM, cause plasma turbulence therein, and will gradually fall to the cluster center. From the observational viewpoint, however, the actual ICM effects on galaxies have remained rather unclear, as evidenced by the paucity of works on comparing the X-ray and optical properties of clusters.

Recently we achieved several important discoveries on the ICM effects of cluster galaxies:
(1) By measuring radial profiles of I-band galaxy light and ICM mass of 34 clusters, we have detected a significant evolution from z=0.9 to z=0.1 in galaxy versus ICM distributions; in lower redshifts, the galaxy component has become more centrally-concentrated relative to the ICM sphere. We further confirmed that the galaxy infall cannot be fully explained as a gravitational effect. This novel discovery provides clear evidence for the long-term “ICM drag” picture as we expected.

(2) To explore more details of the ICM effects on galaxies, we studied ram-pressure-strippings in both nearby galaxies as well as distant ones.
(2.1) Nearby spiral galaxy NGC 4388 in the Virgo cluster. Combining the X-ray data and Subaru narrowfilter + spectroscopic data, we discovered X-ray photoabsorption by the stripped HI tail, and four intracluster star formation regions in the tail.
We achieved a novel picture:
(2.2) Abell 851 at z~0.4. Using the Suprime-Cam z and narrowfilter data, we detected nine candidates of extended ionized gas cloud out of their host galaxies. The brightest candidate appears in a form of >80-kpc-scale tail, and its host galaxy exhibits a post-starburst signature.
These results indicate that the galaxy is in a quick transition phase probably driven by the ICM stripping.

Combining these result, we become more and more confident of our idea that the cluster hot plasmas are significantly affecting the member galaxies, not only on the spatial distributions, but also on their internal structures.

12月4日(水)

キャンパス

三鷹

セミナー名

理論コロキウム

臨時・定例の別

定例

日時

12月4日（水曜日）14時10分～15時10分

場所

コスモス会館会議室

講演者

堀 安範 氏

所属

理論研究部

タイトル

低温度星周りの惑星の姿に迫る

Abstract

NASAが打ち上げたKepler宇宙望遠鏡の活躍により、地球サイズの惑星分布まで
統計的に議論出来る時代になって来た。次はいよいよ、惑星の形成環境および
形成過程を知る直接的な手掛かりとなる、系外惑星本体の姿 (例えば、大気や
全体組成)へ迫る段階に来ている。とりわけ、多様な全体組成を有する地球型惑
星形成を理解する上では、大気および内部組成(惑星の特徴付け)が重要となる。
　現在の観測精度では、太陽よりも小さな低温度星(M型星)周りの地球型惑星が
現実的なターゲットとなっている。これまでに、トランジット観測から大気ス
ペクトルが得られたsuper-Earthも低温度星周りの惑星 3例だけである。
こうした惑星は、水素リッチな大気を保持する, あるいは水に富む惑星である
可能性が示唆されている。今後の観測でも次々に見えて来る情報である、大気
組成および水の存在は、太陽系外の地球型惑星の起源を探る指標となって来て
いる。そこで、本発表では、以下について紹介する。

(1) 観測チームと共同で進めて来たSuper-Earth大気の観測結果、
(2) 惑星形成理論から予想される低温度星周りの sub/super-Earthの
　　原始大気および水の存在量
(3) Sub/Super-Earthの大気散逸の結果

こうした結果を踏まえ、惑星のhabitabilityや起源を議論したいと考えている。

連絡先

名前：山崎 大

12月5日(木)

キャンパス

三鷹

セミナー名

VLBIコロキウム

臨時・定例の別

定例

日時

12月5日（木曜日）15時　～　16時

場所

中央棟(南)2階VLBIセミナー室

講演者

亀谷　収

所属

水沢VLBI観測所

タイトル

VLBI Monitor of SgrA* at 22GHz using Mizusawa 10m radio telescope and JVN

Abstract

VLBI monitoring observation of the flux density of Sagittarius A* (Sgr A*)
at 22GHz has been performed every day since 11 February of this year.
The purpose of the observation is to know the timing of intensity
increase of Sgr A* due to the G2 cloud approaching event. Mizusawa
10m antenna, Takahagi 32m antenna, and Gifu 11m antenna are the main
element antennas of this VLBI monitoring. Kashima 34m antenna and
Tsukuba 32m antenna sometime join it. The details of the observing
system and some results of the observation are discussed.

連絡先

名前：MIN　CHEULHONG

備考

テレビ参加の可

12月6日(金)

キャンパス

三鷹

セミナー名

国立天文台談話会

臨時・定例の別

定例

日時

12月6日(金) 16:00-17:00

場所

大セミナー室

講演者

廣瀬 敬

所属

東京工業大学 地球生命研究所

タイトル

「東工大地球生命研究所における研究戦略：地球と生命の起源の解明に向けて」

Abstract

世界トップレベル研究拠点プログラム(WPI)により、東工大に地球生命研究所(ELSI)が昨年末に設立された。当研究所では、地球の起源、さらには生命の起源の解明を目的としている。生命が初期の地球上に誕生した以上、両者を密接に関連した問題として捉えることが重要である。地球の起源と初期地球の環境は、惑星形成理論モデルと地質学的観察のミッシングリンクであり、未解明の部分が多く残されている。生命の誕生に関する研究も、主に非生物的化学進化実験によるボトムアップ研究と現世の生物を用いたトップダウン研究の狭間にある。セミナーでは、ELSIの研究戦略を具体的に紹介する。

連絡先

名前：田中雅臣

以上