2024.2.12-2024.2.18

February 13 Tue 10:00-11:30
太陽系小天体セミナー
Zoom


February 13 Tue 11:00-12:00
SOKENDAI Doctoral Thesis Preliminary Evaluation
hybrid; Large Seminar Room in Subaru Building and Zoom


February 14 Wed 14:30-15:30
ALMA-J seminar
hybrid; Room 102 in the ALMA building and Zoom


February 14 Wed 15:30-16:30
NAOJ Science Colloquium
hybrid; Lecture room and Zoom


February 16 Fri 16:00-17:00
NAOJ Seminar
hybrid; Large Seminar Room in Subaru Building and Zoom


詳細は下記からご覧ください。

=============== February 13 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:2月13日(火曜日)10時00分~11時30分
場所:zoom
講演者:有松 亘
タイトル:中・大型太陽系外縁天体による恒星掩蔽キャンペーン観測の現状
Abstract:既知の太陽系外縁天体による恒星掩蔽イベントの観測は、外縁天体のサイズ・形状の決定、および衛星や環、表面大気への制約を得るうえで極めて有用である。本発表では現在国内の複数の観測装置を用いて実施している外縁天体恒星掩蔽キャンペーン観測の現状を報告する。

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

=============== February 13 Tue ===============

Campus:Mitaka
Seminar:SOKENDAI Doctoral Thesis Preliminary Evaluation
     総研大博士学位論文予備審査会
Regularly Scheduled/Sporadic:Sporadic
Date and time:February 13, 2024 11:00~12:00

Place : Large Seminar Room and Zoom

Speaker:Yuta Tashima
Title:Elucidation of galactic magnetic field structure by pseudo-observation focusing on depolarization

Facilitator
-Name:Nozomu Tominaga, Hideyuki Kobayashi, Natsuko Fujii (Graduate Student Affairs Unit)

=============== February 14 Wed===============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: February 14 (Wed) 14:30-15:30
Place: hybrid (room 102 in the ALMA building and Zoom)

Speaker: Yulong GAO
Affiliation: School of Astronomy and Space Science, Nanjing University, Nanjing, China
Title: Unraveling the Low-Metallicity Merging Dwarf Galaxies: Insights into Starburst and Metal Dilution/Enrichment

Abstract:
Understanding the physical mechanisms driving starbursts within dwarf galaxies remains a challenge in astrophysics. Moreover, the impact of mergers on star formation activity in these galaxies remains unclear. In this talk, we employ observations from the VLT/MUSE and ALMA to investigate how the merger process influences star formation activities in metal-poor dwarf galaxies, focusing on galaxies of Haro 11 and NGC 4809/4810. Haro 11, situated in the late-stage merger phase, exhibits similar morphology and kinematics to the Antennae galaxy, offering valuable insights into the merger-induced starburst phenomenon. Conversely, the ongoing collision between NGC 4809 and NGC 4810 presents a unique opportunity to examine the effects of mergers on dwarf galaxies in real time, particularly within their overlapping regions. We find post-merger between low mass galaxies (e.g., Haro 11) can trigger global starburst, similar to ULIRGs. Notably, Haro 11 could be the analog of high-z dwarf starbursts and the potential progenitor of the nearby less massive elliptical galaxies. Furthermore, we find that NGC 4809/4810 interaction zone show enhanced SFR (sSFR), and deficient metallicity, indicating the capacity of dwarf galaxy mergers to instigate significant star formation activity even within metal-poor environments. Additionally, we detect clear evidence of metal enrichment resulting from the Type Ic SN 2011jm within NGC 4809, representing a pioneering detection of chemical pollution through stellar feedback beyond the Local Volume. These findings shed light on the underlying mechanisms driving starburst and stellar feedback processes within the dwarf galaxies.

=============== February 14 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Feb. 14 (Wed.), 15:30-16:30
Place: the lecture room / Zoom (hybrid)

Speaker: Ryota Kitamura
Affiliation: The University of Tokyo (M1)
Title: Review on Pan et al. (2022) “The terrestrial planet formation around M dwarfs: in situ, inward migration, or reversed migration”
Abstract of the paper:
Terrestrial planets are commonly observed to orbit M dwarfs with close-in trajectories. In this work, we extensively perform N-body simulations of planetesimal accretion with three models of in situ, inward migration, and reversed migration to explore terrestrial formation in tightly compact systems of M dwarfs. In the simulations, the solid discs are assumed to be 0.01 per cent of the masses of host stars and spread from 0.01 to 0.5 au with the surface density profile scaling with r−k according to the observations. Our results show that the in-situ scenario may produce 7.77+3.23 −3.77 terrestrial planets with an average mass of 1.23+4.01 −0.93 M⊕ around M dwarfs. The number of planets tends to increase as the disc slope is steeper or with a larger stellar mass. Moreover, we show that 2.55+1.45 −1.55 planets with a mass of 3.76+8.77 −3.46 M⊕ are formed in the systems via inward migration, while 2.85+1.15 −0.85 planets with 3.01+13.77 −2.71 M⊕ are yielded under reversed migration. Migration scenarios can also deliver plentiful water from the exterior of the ice line to the interior due to more efficient accretion. The simulation outcomes of the reversed migration model produce the best match with observations, being suggestive of a likely mechanism for planetary formation around M dwarfs

Speaker: Miho Tan
Affiliation: SOKENDAI (M1)
Title: Effect of stellar wind on SS433’s jet propagation
Abstract:
SS433 is an X-ray binary system consisting of a star and a compact star, and the compact star is known to emit spiral binaries. The jets propagate more than 100 pc; in Ohmura et al (2021) and other groups, uniform jets injected from 1 pc propagated 100 pc. But one of the important questions is how to travel to 1pc from the ejection region.
Therefore, in this study, we evaluate the propagation of the jet within 1pc including the effect of stellar winds. Since the orbital period of the binary is shorter than the jet propagation timescale, we assume the propagation area becomes turbulence formed by the stellar wind. We put turbulent velocity fields of 0.1% and 0.01% of the jet velocity in the ambient around the jet to see the effect of the turbulence on the jet propagation.

Facilitator
-Name: Doris Arzoumanian

Comment: English

=============== February 16 Fri==============

Campus:Mitaka
Seminar:NAOJ Seminar
Regularly Scheduled/Sporadic:Regular
Date and time:February 16, 2024 16:00-17:00
Place:Zoom/Large Seminar Room (hybrid)

Speaker:Prof. Hideyuki Kobayashi
Affiliation:National Astronomical Observatory of Japan (NAOJ)
Title:Japanese VLBI development and research that I have been involved in

Abstract: Japanese VLBI development and research that I have been involved in, are reviewed. The VSOP programme, the world’s first space VLBI observation with the HALCA satellite launched in 1997, VERA which is specialized in astrometry and began construction in 2000, as well as the organisation of the East Asian VLBI observation network with the development of the domestic VLBI network are described. Expectations for the next generation of radio telescopes, the SKA, are also discussed.

Facilitator
-Name:Takashi Moriya

2024.1.29-2024.2.4

January 30 Tue 10:00-16:40
SOKENDAI Progress Report Defense in the second semester, AY2023
2023年度後期 総研大研究中間レポート発表会
hybrid; 中央棟(北)1階 講義室およびZoom


January 30 Tue 10:00-11:30
太陽系小天体セミナー
Zoom


January 31 Wed 10:00-12:00
SOKENDAI Doctoral Thesis Dissertation review
総研大博士学位論文予備審査会
hybrid; Lecture Room and Zoom


January 31 Wed 10:30-12:00
SOKENDAI Colloquium
hybrid; Large Seminar Room in Subaru Building and Zoom


January 31 Wed 15:30-16:30
NAOJ Science Colloquium
hybrid; the 3F seminar room in Instrument Development Building No.3 and Zoom


February 1 Thu 14:00-15:00
Tea Talk
Zoom


詳細は下記からご覧ください。

=============== January 30 Tue ===============

キャンパス:三鷹
セミナー名:2023年度後期 総研大研究中間レポート発表会
(SOKENDAI Progress Report Defense in the second semester, AY2023)
定例・臨時の別:臨時
日時:2023年1月30日(火) 10:00~16:40
場所:中央棟(北)1階 講義室およびZoom

講演者:柿元 拓実(10:00~)(Takumi Kakimoto)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:The formation history of a massive quiescent galaxy in a group environment at z = 4.53

講演者:中野 すずか(10:50~)(Suzuka Nakano)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:塵に埋もれた活動的な超巨大ブラックホールの発掘を可能とするサブミリ波帯熱源診断法の開発

講演者:渡辺 くりあ(13:00~)(Kuria Watanabe)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:Uncovering the Physical Origin of Elemental Abundances in Early Galaxies Formation through Observations and Modeling

講演者:波多野 駿(13:50~)(Shun Hatano)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:Exploring for Intermediate Mass Black Holes with Optical Spectra and Near-infrared Luminosity Variability Data.

講演者:内藤 由浩(15:00~)(Yoshihiro Naito)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:Spectroscopic study of Alfvén waves in coronal holes as an energy source for the fast solar wind acceleration

講演者:佐藤 慶暉(15:50~)(Yoshiaki Sato)
所属:総研大 天文科学専攻 (the Department of Astronomical Science, SOKENDAI)
タイトル:Study of Electron Acceleration in Solar Flares with X-ray Focusing-Imaging Spectroscopy and Test-Particle Simulation

世話人の連絡先
-名前:大学院係 松田

=============== January 30 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30日(火曜日)10時00分~11時30分
場所:zoom
講演者:紅山仁
所属:東京大学
タイトル:地球接近小惑星の観測計画2024
Abstract:発表者が2024年に実施する二件の地球接近小惑星の観測計画について発表します。多くの方々のコメントを歓迎いたします。

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 31 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 31, 2024 10:00-12:00
Place :Lecture Room and Zoom

Speaker:Yui Kasagi
Title:Unveiling Atmospheric Features of Faint Substellar Companions from High-Resolution Near-Infrared Spectra

Facilitator
-Name:Nozomu Tominaga, Hideyuki Kobayashi, Kaya Kitabayashi (Graduate Student Affairs Unit)

Comment:
https://guas-astronomy.jp/CampusLife/doctor_report.html

=============== January 31 Wed==============

Campus:Mitaka
Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:January 31, 2024 10:30-12:00
Place:Large Seminar Room in Subaru Building and Zoom

Speaker: Shubham Bhardwaj
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Maria Dainotti, Nozomu Tominaga, Kazunari Iwasaki)
Title: GRB Redshift Estimation Using Machine Learning

Facilitator
-Name:Matsuda, Graduate Student Affairs Unit

=============== January 31 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Jan. 31 (Wed.), 15:30-16:30
Place: the 3F seminar room in Instrument Development Building No.3 / Zoom (hybrid)

Speaker: Shun Hatano
Affiliation: NAOJ (M2)
Title: Origin of high-ionization lines found in extremely metal poor galaxies.
Abstract:
The extreme metal poor galaxies (EMPG) exhibit intense high-ionization emission lines, such as He II4686, unexplained by stellar synthesis models. Umeda et al. (2022) employed CLOUDY and MCMC to reproduce the observed spectrum, revealing an unidentified non-thermal radiation source. In this study, we introduce [Ne V]3426 emission (97.1 eV) and estimate spectral indices and luminosities for EMPGs in the 54.4-97.1 eV range. Confirming that non-thermal radiation dominates the 54.4-97.1 eV range for all the galaxies with [Ne V]3426 detections, we discuss the origin of the non-thermal radiation.

Speaker: Ryota Hatami
Affiliation: NAOJ (M1)
Title: Synthesis of Sc, Ti, and V in core-collapse supernovae
Abstract:
A supernova explosion is an explosive phenomenon that occurs at the end of the life of a massive star. However, the explosion mechanism has not yet been clarified. As a clue to investigate the explosion mechanism, we focused on nucleosynthesis. Metal-poor stars reflect the result of explosive nucleosynthesis in supernova explosions of first stars, and reproducing the chemical abundances of metal-poor stars is one of the important issues in the nucleosynthetic calculation. Recently correlations among Sc, Ti, and V are observationally identified.
Nevertheless, the abundances of Sc, Ti, and V in metal-poor stars have not been reproduced by nucleosynthesis calculations based on the results of hydrodynamical simulation. This is because one of the possible causes is that the explosion mechanism is not yet understood. Then, we attempted to constrain the explosion mechanism by (1) performing nucleosynthesis calculations with setting temperature, density, neutrino flux, etc. as parameters to find physical conditions which reproduce the observed chemical composition of metal-poor stars, and (2) examining the feasibility of these conditions by comparing them with 2D explosion simulations. In this talk, the progress of (1) and (2) will be discussed.

Facilitator
-Name: Masamitsu Mori

Comment: English

=============== February 1 Thu==============

キャンパス:三鷹 野辺山 水沢 岡山 ハワイ
セミナー名:Tea Talk
定例・臨時の別:臨時
日時:2/1(木)14:00~15:00
場所:Zoom
講演者:平松 正顕
所属:天文情報センター周波数資源保護室
タイトル:世界無線通信会議とドバイ4週間の旅
言語:日本語(PPTは英語も併記)

世話人の連絡先:
-名前:藤田登起子

備考:
参加方法:Zoom

2024.1.22-2024.1.28

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

2024.1.15-2024.1.21

January 16 Tue 10:00-11:30 太陽系小天体セミナー
Zoom


January 17 Wed 10:30-12:00 SOKENDAI Colloquium
Large Seminar Room in Subaru Building and Zoom (hybrid)


January 17 Wed 14:30-15:30 ALMA-J seminar
Room 102 in the ALMA Building and Zoom (hybrid)


January 17 Wed 15:30-16:30 NAOJ Science Colloquium
Zoom


January 18 Thu 10:00-12:00 SOKENDAI Doctoral Thesis Dissertation review
Lecture Room and Zoom (hybrid)


January 18 Thu 15:30-17:30 SOKENDAI Doctoral Thesis Dissertation review
Lecture Room and Zoom (hybrid)


January 19 Fri 10:30-12:00 Solar and Space Plasma Seminar
Central Building (North) / 310 and Zoom (hybrid)


詳細は下記からご覧ください。

=============== January 16 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16日(火曜日)10時00分~11時30分
場所:zoom
講演者:宇田豊和
所属:Aiharasoft
タイトル:ハワイ・マウナケア星空ライブからの流星自動検出システム概要
Abstract:ハワイ・マウナケア星空ライブからの流れ星自動検出システムを構築しました。
2022年1月より、大きな流れ星を検出すると、Xでポストする運用を行っています。
今回の発表では、このシステムの概要、流れ星の検出アルゴリズム概要、
ふたご座流星群などの検出状況、現状の問題点、課題についてご説明します。

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 17 Wed ===============

Campus:Mitaka
Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:January 17, 2024 10:30-12:00
Place:Large Seminar Room in Subaru Building and Zoom

Speaker: Kazuki Watanabe
Affiliation: SOKENDAI 1st year (M1) (Supervisor: Yoshinori Uzawa, Takafumi Kojima, Tai Oshima)
Title: Development of a sub-THz MKID Camera for Deep Space Observation

Speaker: Miho Tan
Affiliation: SOKENDAI 1st year (M1) (Supervisor: Mami Machida, Tomoya Takiwaki, Kazunari Iwasaki)
Title: Effect of an optical star wind on SS433’s jet propagation

Facilitator
-Name:Matsuda, Graduate Student Affairs Unit

=============== January 17 Wed===============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: January 17 (Wed) 14:30-15:30
Place: hybrid (Room 102 in the ALMA building and Zoom)

1st speaker: Yuzuki Nagashima
Affiliation: Fukushima university / NAOJ
Title: High-precision SFR mapping of the nearby galaxy NGC 1068 using ALMA 100 GHz continuum and HST Paα line and the effect of DIG contamination.

Abstract:
The star formation rate (SFR) is an important indicator in the context of galaxy evolution. However, it is not easy to accurately measure the SFR in external galaxies. For example, the most common method is to use radiation from the HII region, but the to assume temperature of the HII region and the contribution of other radiation sources make it difficult to accurately estimate the SFR. Furthermore, in the infrared and optical wavelength bands, the effect of dust extinction is significant and needs to be corrected. Therefore, it is important to observe in the millimeter and sub-millimeter wavelength bands with ALMA, which are not affected to dust extinction, especially, which has high sensitivity and high resolution. In recent years, with the improvement of data accuracy, a method to isolate, identify, and extract whether the source of ionized gas is from star formation or not is being established. By identifying and subtracting stronger ionization sources (e.g., AGN origin) and weaker (Diffuse Ionized Gas; DIG origin) than star formation sources, SFRs that are less contradiction with SFRs derived from multiple tracers have been reported (e.g., Michiyama et al. 2020). Michiyama et al. 2020).
We produced a precise SFR map for the nearby galaxy NGC 1068 by comparing the two different ionized gas tracers, free-free emission and hydrogen recombination line the Paα, and by considering the effect of DIG.
In this talk, I will introduce how to make an accurate SFR map and the result.
In addition, I will focus on the DIG correction.

2nd speaker: Mahoshi Sawamura
Affiliation: University of Tokyo / NAOJ
Title: No galaxy-scale [CII] outflow detected in a z=6.72 red quasar with ALMA

Abstruct:
It has been claimed that active galactic nucleus (AGN)-driven massive outflows, which would happen during a transition phase from an obscured dusty quasar to a normal blue quasar, are the key physical process in driving the co-evolution of galaxies and supermassive black holes (SMBHs). Partially dust-obscured red quasars are thought to be the immediate phase of this transition. However, while many blue quasars at z = 6~7 have been found in recent years, it is still hard to identify red quasars at that epoch due to their apparent faintness. Deep, wide-area surveys and subsequent multi-wavelength follow-up observations are thus required to identify such red objects and test the above evolutionary scenario. Here we report our ALMA cycle 7 observations of the z = 6.72 red quasar HSC 120505.09−000027.9 (J1205−0000). This is one of the highest redshift (z > 6) red quasars originally identified by our deep Subaru Hyper Suprime-Cam (HSC) survey. It is apparently faint, but is intrinsically as luminous as −24.4 mag at rest-UV and hosts a massive BH of 2.2 × 10^9 Msun. It is also known to be N V and C IV BAL object, indicating the existence of nuclear outflows. We successfully detected both the [CII] 158 μm line and the underlying rest-FIR continuum emission (resolution ~0.6″, 1σ ~ 0.1 mJy/beam at dV = 75 km/s). The continuum is very bright, with the estimated luminosity of 2.3 × 10^12 Lsun (or equivalently SFR ~ 485 Msun/yr), which indicates that the host galaxy of this red quasar is indeed a starburst system. However, the detailed analysis of the visibility data suggests that the bulk of this IR emission originates from a spatially unresolved compact component, likely the AGN itself. Hence the actual SFR could be much smaller. Regarding the AGN feedback, our observations do not conclusively assert the presence of [CⅡ] outflows. One possible interpretation of this is that the spatial scale of the outflow is not large enough to reach the host galaxy. However, we propose that this red quasar is indeed in a key evolutionary phase of AGN feedback. We will also discuss possible future observations to explore the existence of this wing component.

=============== January 17 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Jan. 17 (Wed.), 15:30-16:30
Place: Zoom

Speaker: Bruce Gendre
Affiliation: Australian National University
Title: Progenitors of ultra-long gamma-ray bursts: an ultra-long and ultra-slow developing story
Abstract:
Gamma-ray bursts are fantastic explosions seen at cosmological distances, and one of the most extreme high energy events of the Universe. Because of their distance, understanding the phenomenon at play is challenging. In this seminar, I will review the GRB phenomenon, what we already know about the progenitor of those events, focusing on the most unknown kind of event, the ultra-long ones, and how we use the current technology for improving our knowledge.

Facilitator
-Name: Maria Giovanna Dainotti
Comment: English

=============== January 18 Thu==============

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 18, 2024 10:00-12:00
Place :Lecture Room and Zoom

Speaker:Raiga Kashiwagi
Title:Instability and Evolution of Shocked Clouds Formed by Collisions between Filamentary Molecular Clouds

Facilitator
-Name:Nozomu Tominaga, Hideyuki Kobayashi, Kaya Kitabayashi (Graduate Student Affairs Unit)

Comment:
https://guas-astronomy.jp/CampusLife/doctor_report.html

=============== January 18 Thu==============

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 18, 2024 15:30-17:30
Place :Lecture Room and Zoom

Speaker:Rikuto Omae
Title:Probing the Magnetic Fields of Distant Galaxies to Unravel the Evolution of Galactic Magnetic Fields

Facilitator
-Name:Nozomu Tominaga, Hideyuki Kobayashi, Kaya Kitabayashi (Graduate Student Affairs Unit)

Comment:
https://guas-astronomy.jp/CampusLife/doctor_report.html

=============== January 19 Fri==============

Campus: Mitaka
Seminar: Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic: Sporadic
Date and time:19th January (Fri), 10:30-12:00
Place: hybrid; Central Building (North) / 310 and Zoom

Speaker:Dr. Ryoko Ishikawa
Affiliation:NAOJ
Title:3D mapping of the magnetic field in the whole atmosphere of an active region plage with the CLASP2.1 sounding rocket experiment
Abstract:Probing the magnetic field throughout the solar atmosphere is critically important for understanding the energy transfer from the photosphere to the corona. However, there is an overwhelming lack of empirical information on the magnetic field in the upper chromosphere and the layers above, where the magnetic pressure dominates the gas pressure (β < 1). To this end, a novel approach is to measure and model the polarization of magnetically-sensitive ultraviolet (UV) spectral lines. The series of sounding rocket experiments CLASP (2015), CLASP2 (2019) and CLASP2.1 (2021) have demonstrated that UV spectro-polarimetry is indeed a suitable diagnostic tool for investigating the magnetic fields in the whole solar chromosphere. On October 8, 2021, CLASP2.1 measured the Stokes profiles of the 280 nm spectral region at 16 consecutive slit positions covering a two-dimensional field of view in an active region plage. This near-UV spectral region contains the resonance lines of Mn I (which provide information on the lower chromosphere) and the Mg II h & k lines (which provide information on the middle and upper chromosphere). Combined with coordinated observations with the Solar Optical Telescope (SOT) aboard the Hinode satellite, we obtained a line-of-sight magnetogram covering a sunspot penumbra and a plage (moss) region at multiple heights from the photosphere to the top chromosphere. The 3D mapping enables how the magnetic patches expand with height and how much magnetic flux reaches higher in the chromosphere. The obtained magnetogram is compared with the high-resolution images recorded by IRIS and SDO/AIA, revealing the connectivity between the magnetic structure in the chromosphere and the coronal loops.

Facilitator
-Name:Akiko Tei

Comment:English

2023/10/22~2023/10/29

Oct 23 Mon 14:30-15:30 ALMA-J seminar hybrid (ROOM102 in ALMA building and ZOOM)


Oct 24 Tue 10:00-11:30 太陽系小天体セミナー zoom


Oct 24 Tue 16:00-17:00 NAOJ Seminar zoom/ Large seminar room in Subaru Building


Oct 25 Wed 10:30-12:00 SOKENDAI Colloquium Large Seminar Room in Subaru Building and Zoom


Oct 25 Wed 14:30-15:30 ALMA-J seminar hybrid (Small seminar room in Subaru building and ZOOM)


Oct 25 Wed 15:30-16:30 NAOJ Science Colloquium The large seminar room / Zoom (hybrid)

詳細は以下をご覧下さい。

=============== October 23 Mon===============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Oct 23rd (Mon) 14:30-15:30
Place: hybrid (ROOM102 in ALMA building and ZOOM)
Speaker: Alfonso Trejo
Affiliation: UNAM
Title: The participation of Mexico in the ngVLA
Abstract:
The ngVLA, led by the National Radio Astronomy Observatory (NRAO), will be the largest radio interferometer ever built in the northern hemisphere. With more than 200 antennas distributed across the US, Canada, and Mexico, the array will reach spatial resolutions and sensitivities without precedents. The ngVLA will open a new window on the universe through ultra-sensitive imaging of spectral lines and continuum emission with milliarcsecond resolution.

We will discuss current work the Mexican community is doing for selecting the final MID sites in Mexico, simulations to characterise the array with its critical longest north-south baselines, enabled by the antennas in Mexico. Briefly, we will discuss the observatory designs that Mexico is leading: antenna base foundations, antenna site layouts, and antenna supporting buildings.
To finalize, I will outline the plans for national and international conferences and workshops, aimed at audiences from newcomers to advanced users.

In the last part of the talk, I will briefly introduce the Nearby Evolved Stars Survey (NESS) project that aims to study a volume-complete sample of mass-losing stars in the Solar neighbourhood. A summary of its main science objectives and how they are enabled by JCMT, APEX, NRO, and ALMA observations will be provided. In particular, we will focus on the ongoing ACA observations and some of its preliminary results. Finally, we discuss synergies with the current VLA and the future ngVLA, including astrometry studies.

Organizers: Gianni Cataldi , Hiroshi Nagai

=============== October 24 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:10月24日(火曜日)10時00分~11時30分
場所:zoom
講演者:浦川聖太郎

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

=============== October 24 Tue===============

Campus:Mitaka
Seminar:NAOJ Seminar
Date and time:Oct 24 Tue 16:00-17:00
Place:zoom/ Large seminar room in Subaru Building
Speaker:Dr,Roland Bacon
Affiliation:Observatoire de Lyon
Title:WST – The Wide Field Spectroscopic Telescope
Abstract:The WST project aim to study and built an innovative 10-m class wide-field spectroscopic survey telescope (WST) in the southern hemisphere with simultaneous operation of a large field-of-view (5 sq. degree) and high multiplex (20,000) multi-object spectrograph facility with both medium and high resolution modes (MOS), and a giant panoramic integral field spectrograph (IFS). The ambitious WST top-level requirements place it far ahead of existing and planned facilities. In just its first 5 years of operation, the MOS will target 250 million galaxies and 25 million stars at medium resolution + 2 million stars at high resolution, and 4 billion spectra with the IFS. WST will achieve transformative results in most areas of astrophysics. The combination of MOS and IFS spectroscopic surveys is one of the key aspects of the project. It is very attractive because of the high complementarity between the two approaches. I will detail this innovative point using the example of the MOS and MUSE surveys performed in the CFS region. The project aims to be the next major post-ELT project. It is supported by a large consortium of very experienced institutes plus ESO, representing 9 European countries and Australia.

Facilitator
-Name:Oouchi, Masami


=============== October 25 Wed===============

Campus:Mitaka
Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:October 25, 2023 10:30-12:00
Place:Large Seminar Room in Subaru Building and Zoom

Speaker: Ryota Ichimura
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Hideko Nomura, Akimasa Kataoka, Nanase Harada)
Title: Gas-Grain Model for Carbon Isotope Fractionation of COMs in Star-Forming Cores
Abstract:
Understanding the isotopic composition of ice molecules in star-forming cores is a powerful tool for investigating the origin of organic molecules in solar system objects. Recent high-resolution ALMA observations have measured the carbon isotopic ratios (12C/13C) of Complex Organic Molecules (COMs) in the Class 0 low-mass protostellar object IRAS 16293-2422B. The measured isotopic values are comparable to the average values in the local interstellar medium or show lower values, that is enriched in 13C. Several model calculations , observations, and laboratory experiments suggest that COMs are formed on the dust grain surface during star-formation. However, there are no model calculations of carbon isotope fractionations of COMs, and the origin of observed fractionations is not well understood.
In this study, we use a physical model of a star-forming core undergoing gravitational contraction, and performing chemical reaction network calculations considering three phases: the gas phase, the grain surface, and the ice mantle. And then we systematically investigate the carbon isotopic fractionations of COMs including formation of icy COMs prior to star formation and subsequent their sublimation into the gas phase following star formation.
Before the protostar formation, the 12C/13C ratios of icy small carbon species exhibit bimodal profile: the derivative species from CO are slightly enriched in 13C, while those succeeded from C and C+ are depleted in 13C owing to isotope exchange reactions. Icy COMs, originating from simpler species, also show this bimodality or deviation from it due to mixing. Sublimated COMs reflect the 12C/13C ratios of their icy counterparts. However, parts of COMs originate from radical and ionised species at higher temperature (T > 20 K), which change the 12C/13C ratios of the molecules from that of their ice in the prestellar phase. Eventually, in our base model COMs exhibit more fractionated rather than the observed value. The additional dust surface reactions involving atomic carbon having occurred at shorter timescales relative to isotope exchange reactions, lead to formation of COMs originated from less fractionated atomic carbon.
Consequently, additional C-atom reactions mitigate isotope fractionation, and roughly reproduces the non-fractionated observed values. Nonetheless, further investigation is necessary to reproduce the observed values more comprehensively.

Speaker: Tomohiro Yoshida
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Hideko Nomura, Misato Fukagawa, Akimasa Kataoka)
Title: The First Spatially-resolved Detection of 12CN/13CN in a Protoplanetary Disk and Evidence for Complex Carbon Isotope Fractionation

Facilitator
-Name:Matsuda, Graduate Student Affairs Unit

=============== October 25 Wed===============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Oct 25th (Wed) 14:30-15:30
Place: hybrid (Small seminar room in Subaru building and ZOOM)
Speaker: Yoshihide Yamato
Affiliation: University of Tokyo
Title: ALMA Observations of the Disk around the Young Bursting Star V883 Ori: Spatial Distributions and Chemistry of Complex Organic Molecules
Abstract:
Complex organic molecules (COMs), potential precursors of prebiotic molecules, are key to understanding the chemical evolution from the interstellar medium to planetary systems. However, the complex organic chemistry in protoplanetary disks, the immediate birthplace of planets, is still poorly understood. In this talk, I will present ALMA Band 3 observations of COMs in the disk around the young bursting star V883 Ori, which provides a unique opportunity to observe thermally sublimated COMs thanks to its warm nature. We detected ten oxygen-bearing COMs including 13C isotopologues in the disk. The radial distributions of the COM emission, revealed by detailed line profile analyses, show a common inner emission cavity, indicating that the COM emission may be hidden by the dust continuum emission due to the high temperature in the disk midplane caused by the viscous accretion heating. We also measured the abundance ratios of COMs with respect to CH3OH and the isotopic ratios (12C/13C and D/H) of COMs for the first time in a protoplanetary disk. The abundances of COMs are systematically higher than those in the warm protostellar envelopes of IRAS 16293-2422. The 12C/13C ratios of different COMs are consistently lower (~20-30) than the canonical ISM ratio (~69). The upper limits of the COM D/H ratios (< 0.01) are also lower than those in IRAS 16293-2422. These high COM abundances and peculiar isotopic ratios could be explained by the efficient formation of COMs from the 13C-enriched CO on the lukewarm dust grain surfaces. We will discuss the implications of these results for the chemical evolution of COMs in protoplanetary disks.

Organizers: Gianni Cataldi , Hiroshi Nagai

=============== October 25 Wed===============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Oct. 25 (Wed.), 15:30-16:30
Place: The large seminar room / Zoom (hybrid)

Speaker: Haruka Kusakabe
Affiliation: NAOJ/JSPS

Title: CGM observations in emission

Abstract:
The evolution of galaxies is directly linked to the gas reservoirs surrounding them, so-called, “the circum-galactic medium (CGM)”. Gas and metals are exchanged via inflows and outflows through the CGM, which is an interface between the interstellar medium (i.e., galaxy) and intergalactic medium (the rest of the Universe). The CGM has been studied with absorption lines imprinted in spectra of bright background quasars (tomography), but this method is limited to line of sight and cannot provide the 2D spatial distribution of the CGM. Recent sensitive, wide-FoV integral-field spectrographs (such as VLT/MUSE and Keck/KCWI) make it possible to individually detect the CGM in emission, which allows us to map the gas and metals around host galaxies. In this talk, I will review the recent progress in observations and understanding of hydrogen gas and metals around z>~2 galaxies, which are detected as extended Lyα emission (Lyα haloes) and metal-line haloes. I will also connect the CGM observations in emission and absorption and introduce comparisons with simulations.

Facilitator
-Name: Hiroki Nagakura
Comment: English