IoA Seminar 2013 / 2013年度・東京大学・天文学教育研究センター・談話会†
次回以降の談話会†
第222回: 2013/5/16(木) 15:30-16:30†
Speaker: Gu Liyi (Univ. Tokyo/RESCEU)†
Title: Multi-wavelength Probe of Galaxy-Hot Plasma Interaction in Rich Clusters of Galaxies†
Abstract:
Galaxy clusters form as gigantic clumps of dark matter, and their associated
galaxies are pulled together by gravity. The intracluster field is not empty,
in fact, most detected baryons are in form of diffuse gas filling the field,
the "intracluster medium" (ICM, temperature~1e7-1e8 K), which emits mostly
in X-ray. The cluster member galaxies move randomly through the ICM with
transonic speeds.
In nearby clusters of galaxies, the stellar component is spatially much more
concentrated than the ICM, while metals in the ICM distribute more extended
than the stars which have produced them. To explain these puzzling fact,
Makishima et al. (2001) proposed that "galaxies used to have a much extended
distribution, but they have gradually fallen, by interacting with the ambient
hot plasmas, to cluster centre over the Hubble time".
By studying the optical and X-ray properties of 34 clusters, we detected clear
evolution in galaxy light versus ICM mass ratio, so that the stellar component
has indeed become more concentrated than the ICM from z=0.9 to 0.1.
This proves the "galaxy infall" scenario. During infall the metal in interstellar
medium might be transported to the ICM by, e.g., ram pressure stripping.
To explore the nature of galaxy-ICM interaction, we focus on the ram pressure
strippings in the Virgo Cluster/M86 group. At least two tails of stripped galactic
gas were discovered near the M86 region; one behind NGC 4388 emitting in Halpha
and HI, and the other between NGC 4438 and M86 mostly in Halpha. By analysing the
XMM-Newton and Chandra data, we detected X-ray counterpart of both tails. Hot gas
associated with the tails has a temperature of 0.8 keV, and a density of >1e-3
cm^{-3}. This indicates that the stripped galactic gas has been evaporated to
some extent. By analysing Subaru FOCAS data, we identified star forming regions
associated with the NGC 4388 tail, which implies that cooling also plays a role
in such interactions. Furthermore we detected evidence of ICM metal enrichment
by such ram pressure stripping.
東京大学・天文学教育研究センターでは2003年4月から, 院生コロキウムに引き続き, 談話会を開いています.
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標準タイムテーブル†
| 13:30-14:30 | 院生コロキウム | 講義室 |
| 15:30-16:30 | 談話会 | 講義室 |
| 16:30- | お茶の時間 | 講義室横のお茶部屋~講師の方を交えて~ |
世話人†
- 河野 孝太郎: kkohno_at_ioa.s.u-tokyo.ac.jp (_at_を@に置き換えてください)
- 田辺 俊彦: ttanabe_at_ioa.s.u-tokyo.ac.jp (_at_を@に置き換えてください)
- 小西 真広: konishi_at_ioa.s.u-tokyo.ac.jp (_at_を@に置き換えてください)
| # | 日付 | 講演者 (所属) | タイトル |
| 222 | 2013/05/16(Thu) | Gu Liyi(Univ. Tokyo/RESCEU) | Multi-wavelength Probe of Galaxy-Hot Plasma Interaction in Rich Clusters of Galaxies |
| 223 | 2013/05/23(Thu) | 南谷哲宏(東大/IoA) | Physical Properties of Dense Molecular Clumps in the Small Magellanic Cloud |
| 224 | 2013/05/30(Thu) | 田中賢幸(国立天文台) | On the formation time scale of massive cluster ellipticals based on deep near-IR spectroscopy at z~2 |
| 225 | 2013/06/13(Thu) | 新永浩子(国立天文台/チリ観測所) | Submillimeter Astronomy at Mauna Kea |
| 226 | 2013/06/27(Thu) | 戸谷友則(東大) | |
| 227 | 2013/06/28(Fri) 13:30-14:30 | 井上開輝(近畿大) | |
終了した談話会(今年度)†
詳細はこちら: 平成25 (2013) 年度談話会
| # | 日付 | 講演者 (所属) | タイトル |
| 221 | 2013/05/09(Thu) | 遠藤 光(Delft University of Technology) | アストロフォトニクス：オンチップ超伝導分光計DESHIMAの研究開発 |
| 220 | 2013/04/26(Fri) 13:30-14:30 | Malte Schramm(IPMU) | The co-evolution between black hole and galaxy over the past 12 billion years. |
| 219 | 2013/04/18(Thu) | 真喜屋 龍(東大/IoA) | 宇宙論的銀河形成モデルへの新たなフィードバック機構の導入 |
| 218 | 2013/04/11(Thu) | 小麦真也(国立天文台ALMA東アジアセンター) | 星形成則の多変数化：星間物質の基本平面の発見 |
昨年度までの談話会†
![[PukiWiki]](image/pukiwiki.png "[PukiWiki]")
