January 23 Tue 10:00-11:30 太陽系小天体セミナー
Zoom
January 24 Wed 10:30-12:00 SOKENDAI Colloquium
Large Seminar Room in Subaru Building and Zoom (hybrid)
January 24 Wed 13:00-15:00 SOKENDAI Doctoral Thesis Dissertation review
Lecture Room and Zoom (hybrid)
January 24 Wed 13:30-15:00 Solar and Space Plasma Seminar
Insei Seminar Room and Zoom(hybrid)
January 24 Wed 14:30-15:30 ALMA-J seminar
Room 102 in the ALMA Building and Zoom (hybrid)
January 24 Wed 15:30-16:30 NAOJ Science Colloquium
the 3F seminar room in Instrument Development Building No.3 and Zoom (hybrid)
詳細は下記からご覧ください。
=============== January 23 Tue ===============
キャンパス：三鷹
セミナー名：太陽系小天体セミナー
定例・臨時の別：定例
日時：1月23日（火曜日）10時00分～11時30分
場所：zoom
講演者：匠あさみ
世話人の連絡先
名前：渡部潤一
備考：テレビ会議またはスカイプによる参加も可
=============== January 24 Wed ===============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：January 24, 2024 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker: Takumi Kakimoto
Affiliation: SOKENDAI 2nd year (M2) (Supervisor: Masayuki Tanaka, Daisuke Iono, Kiyoto Yabe)
Title: Star formation activity in a massive protocluster at z=4.5
Speaker: Chanoul Seo
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Yuka Fujii, Masahiro Ikoma, Hideko Nomura)
Title: Impact of Magma Redox States on Super-Earth Atmospheres:Unveiling the Connection with Atmospheric Composition
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== January 24 Wed===============
Campus：Mitaka
Seminar：SOKENDAI Doctoral Thesis Dissertation review
総研大博士学位論文予備審査会
Regularly Scheduled/Sporadic：Sporadic
Date and time：January 24, 2024 13:00-15:00
Place ：Lecture Room and Zoom
Speaker：Takaho Masai
Title：A Study on the Design of Receiver Optics and Waveguide Components Towards High-Performance (Sub)millimeter Wave Multibeam Receivers
Facilitator
-Name：Nozomu Tominaga, Hideyuki Kobayashi, Kaya Kitabayashi (Graduate Student Affairs Unit)
Comment:
https://guas-astronomy.jp/CampusLife/doctor_report.html
=============== January 24 Wed==============
Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Sporadic
Date and time：24 January (Wed), 13:30-15:00
Place： hybrid; Insei Seminar Room and Zoom
Speaker：Dr. Yoichiro Hanaoka
Affiliation：NAOJ
Title：Observation of the White-Light Corona at Total Solar Eclipses (Focusing
on Polarization Measurements)
Abstract：Total solar eclipses are good chances to observe the inner white-light corona under a very low background level. Combining the eclipse data and those from spaceborne coronagraphs such as SOHO/LASCO, we can obtain the distribution of the coronal material regardless of the temperature from just above the limb to tens of solar radii.
For this purpose, we carried out eclipse observations several times with amateur observers using polarimetry instruments. Polarimetry is indispensable to separate the K-corona (million-kelvin plasma) from the F-corona (interplanetary dust), and therefore, all the spaceborne coronagraphs have polarimetric capacity.
The results from the eclipses unexpectedly show a systematic difference between the polarimetry results obtained during the eclipses and those by LASCO. The degree of polarization obtained by LASCO is about 30 % less than the eclipse results and it was revealed that combining the eclipse and LASCO data is difficult. This result suggests that the polarimetric calibration of LASCO should be re-examined.
Some future space missions carrying white-light coronagraphs are planned, and they may also have difficulty in polarimetric calibrations. Repeated eclipse observations are expected to provide good calibration data for space coronagraphs. After a consistent calibration becomes possible, the precise distribution of coronal material in the wide range will be obtained.
Facilitator
-Name：Akiko Tei
Comment：English
=============== January 24 Wed==============
Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: January 24 (Wed) 14:30-15:30
Place: hybrid (Room 102 in the ALMA building and Zoom)
Speaker: Kianhong Lee
Affiliation: Tohoku University
Title: ALMA [CII] observations of TN J0924-2201, the radio galaxy at z~5.2
Abstract:
High-redshift radio galaxies are massive star-forming galaxies with powerful radio jets, often located on or below the star-forming main sequence of galaxies, indicating that they are in the process of being quenched. TN J0924-2201 is one of the most distant known radio galaxies, associated with three CO(1-0)-detected companions at z~5.2. In this talk we will present ALMA observations of [CII] 158 um line and the corresponding 1-mm continuum emission of TN J0924-2201. While obtaining the [CII] line and 1mm continuum emission at the host galaxy, our observations revealed no detection at the positions of the three CO(1-0) companions. The derived systematic redshift z_[CII] of the host galaxy from the [CII] is ~5.17, indicating a velocity offset of ~1200 km/s with respect to z_Lya, marking the largest velocity offset between [CII] and Lya recorded at z > 5 to date. Within the host galaxy, we identified an extended [CII] structure with a velocity of ~700 km/s, suggestive of an outflow. This finding aligns with the shell outflow model, providing consistency with the observed large velocity offset of Lya. Assuming three massive CO(1-0) companions are also outflows, their velocities of ~1500 km/s surpass the escape velocity of a 10^13 Msun halo, implying the removal of molecular gas from the system of TN J0924-2201. Our observations and results revealed that we are witnessing a distinctive phase of radio galaxies in their evolution.
=============== January 24 Wed==============
Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Jan. 24 (Wed.), 15:30-16:30
Place: the 3F seminar room in Instrument Development Building No.3 / Zoom (hybrid)
Speaker: Ryota Ichimura
Affiliation: NAOJ (D1)
Title: Carbon Isotope Fractionation of Complex Organic Molecules in Star-Forming Cores
Abstract:
Recent high-resolution and sensitivity ALMA observations have unveiled the carbon isotope ratios (12C/13C) of Complex Organic Molecules (COMs) in a low-mass protostellar source. To understand the 12C/13C ratios of COMs, we investigated the carbon isotopic fractionation of COMs from prestellar cores to protostellar cores with a gas-grain chemical network model. We confirmed that in the prestellar phase, the 12C/13C ratios of small molecules are bimodal: CO and species formed from CO (e.g.,CH3OH) are slightly enriched in 13C compared to the local ISM (by ∼ 10 %), while those from C and C+ are depleted in 13C owing to isotope exchange reactions. COMs are formed from the simple species on grain surface, and thus basically inherit the bimodality of 12C/13C. In the protostellar phase, COMs are formed on the grain surface and in the hot gas (> 100 K) and have different 12C/13C from those in the prestellar phase. We additionally incorporate reactions between gaseous atomic C and H2O ice or CO ice on the grain surface to form H2CO ice or C2O ice suggested by recent laboratory studies. The direct C-atom addition reactions open pathways to form 13C-enriched COMs from atomic C and CO ice. We find that these direct C-atom addition reactions mitigate isotope fractionation, and the model with the direct C-atom addition reactions better reproduces the observations than our base model. Our calculations also show that cosmic-ray ionization rates affect the 12C/13C ratios of COMs.
Speaker: Akifumi Matsumura
Affiliation: The University of Tokyo (M1)
Title: Estimating the characteristics of ejecta from magma ocean for water production on the protoplanet
Abstract:
How water is delivered to rocky planets during the planet-forming stage is a major issue in planetary science. While many previous studies considered water delivery by icy planetesimals, we consider water production by chemical interaction between the primordial atmosphere and the surface of the magma ocean of a rocky planet growing through planetesimal accretion. Previous studies based on this idea assumed that iron oxides in the magma ocean and atmospheric hydrogen are always in constant contact, which must be examined; namely, we need to consider properly how to bring the magma into contact with the atmosphere. In this study, we focus on the reaction between the atmospheric gas and the materials ejected from the magma ocean when planetesimals collide with the magma ocean surface during the growth phase of a planet. I am currently studying the scatter of magma upon the impact of planetesimals on the planet’s surface and its influence on the atmospheric composition. In this talk, I will describe our progress in the research to date and future research plans.
Facilitator
-Name: Kanji Mori
Comment: English