カテゴリー: 総研大コロキウム

総研大コロキウム

2023.12.4-2023.12.10

December　5 Tue 10:00-11:30 太陽系小天体セミナー
Zoom

December 　6 Wed 10:30-12:00 SOKENDAI Colloquium
Large Seminar Room in Subaru Building and Zoom (hybrid)

December 　6 Wed 11:00-12:00 Tea Talk
Zoom

December 　6 Wed 15:30-16:30 NAOJ Science Colloquium
Large Seminar Room in Subaru Building and Zoom (hybrid)

December 　8 Fri 16:00-17:00 NAOJ Seminar
Large Seminar Room in Subaru Building and Zoom (hybrid)

詳細は下記からご覧ください。

=============== December 　5 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：12月5日（火曜日）10時00分～11時30分
場所：zoom
講演者：渡部潤一

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

=============== December 　6 wed===============

Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：December 6, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom

Speaker: Abdurrahman Naufal
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Yusei Koyama, Masayuki Tanaka, Yuichi Matsuda)
Title: Searching for quiescent galaxies in the Spiderweb protocluster with HST grism observation

Speaker: Takaho Masai
Affiliation: SOKENDAI 55h year (D3) (Supervisor: Alvaro Gonzalez, Yoshinori Uzawa, Takafumi Kojima)
Title: The Design of Frequency Independent Optics for (Sub)Millimeter Wave Multibeam Receivers

Facilitator
-Name：Matsuda, Graduate Student Affairs Unit

=============== December 　6 wed==============

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：12/6（水）11：00～12：00
場所：Zoom
Speaker: Séamus Duffy, Research Student, SOKENDAI
Title: Science Outreach in Ireland: Science Education at Birr Castle with I-LOFAR
Abstract: This tea-talk will talk a little bit about Ireland, and also about outreach there, broaching topics such as: who we target, how we target them, what activities and projects do we run, and adapting to Covid and a post-Covid world.

Bio: Séamus Duffy is a current research student at NAOJ working with the SCExAO team, focusing on applications of machine learning and AI to astronomy.
He originally came to Japan in 2017 and worked as an English teacher in Tokyo, where he stayed for four years before returning to Ireland in 2020. In Ireland he worked with the Technological University of the Shannon, Trinity College Dublin, and Dublin Institute for Advanced Studies as the education and engagement manager for the I-LOFAR project at Birr Castle, home of the Leviathan telescope. I-LOFAR is the Irish installation in the low frequency array, a radio telescope network which cover most of the European continent. He has a huge passion for teaching, outreach and inspiring younger minds to get involved with astronomy. During his time in outreach he worked to educate about I-LOFAR and the science being conducted at the telescope to the local population of Birr, local schools, businesses, and government officials. He was particularly interested in conducting outreach in a post-covid environment and utilising online and digital spaces for outreach programmes.

世話人の連絡先：
-名前：藤田登起子

=============== December 　6 wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Dec. 6 (Wed.), 15:30-16:30
Place: the large seminar room / Zoom (hybrid)

Speaker: Moka Nishigaki
Affiliation: NAOJ (D1)
Title: Uncovering the Chemical Evolution of Galaxies from z=0–5 using the UniverseMachine
Abstract:
Cosmic baryon cycling is pivotal to galaxy evolution, and the amount of metals present in galaxies’ ISMs provides a key window into the gas cycling process. Recent JWST metallicity measurements and constraints on galaxy ISM masses have made it possible to recover the chemical evolution history of galaxies. In this talk, I present a novel empirical model that infers the average metallicity evolution of galaxies from redshift z=5 to z=0. Anchored in the UniverseMachine
(Behroozi+19) framework, our model converts observations of gas-phase metallicities across z=0—5 and galaxy ISM masses into constraints on the ISM return fraction, a key parameter quantifying the recycling of metals into the ISM versus expulsion into the CGM. I will show the initial results on how the ISM return fraction changes with mass and redshift.

Speaker: Xingqun Yao
Affiliation: Beihang University
Title: Neutrino Mass Hierarchy from Supernova Nucleosynthesis of Light Elements and the Roles of Unstable Nuclei
Abstract:
The origin of neutrino mass and mass hierarchy is one of the biggest unanswered questions in physics. In this talk I propose an astrophysical method so that the supernova (SN) ν-process nucleosynthesis, which is consistent with the mass hierarchy constrained from various ν-oscillation experiments, should provide independent observational signals of nucleosynthetic products in the specific nuclei such as 138La, 19F, 7Li, 11B and others (so-called ν nuclei) through the ν-flavor oscillation due to the MSW matter effect and the effect of collective oscillation [1].
Core-collapse SNe emits a huge number of neutrinos which bring valuable observational information on how the neutrinos propagate through the high-density matter and change their flavors and how explosive nucleosynthesis occurs. We found that the still unknown mass hierarchy is imprinted in the nucleosynthetic products of ν-nuclei [1,2]. In this talk, I will discuss the mechanism of SN ν-process nucleosynthesis and try to constrain the mass hierarchy by comparing our theoretical prediction of nuclear abundances and observed values in the meteorites and spectrascopy study. Among the calculated results, the abundance ratios of 11B/138La and 19F/16Oprovide exclusively sensitive probes to neutrino mass hierarchy [1]. These ratios are also influenced by the mass cut during the ejection phase of SN materials. These facts provide valuable quantitative tools to constrain the mass hierarchy through precise measurements of nuclear abundances of these ν-nuclei in SiC-X pre-solar grains and comprehensive studies of solar-system abundances.

Facilitator
-Name: Haruka Kusakabe
Comment: English

=============== December 　8 Fri==============

Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：December 8, 2023 16:00-17:00
Place：Zoom/Large Seminar Room (hybrid)

Speaker：Prof. Cecilia Lunardini
Affiliation：Arizona State University

Title：Neutrinos and gravity: multimessenger scenarios
Abstract:Multimessenger astronomy is developing rapidly, and neutrinos are major players in its vast landscape. It is hoped that, in the near future, experimental and theoretical developments will lead to the detection of neutrinos and gravitational waves from the same class of source. I discuss possible scenarios, involving neutrinos and gravitational waves from core collapse supernovae, and from binary mergers of matter-rich compact objects (for example, two neutron stars). I will also discuss tidal disruption events, where a star is torn apart and eventually accreted by a supermassive black hole. These events, which produce flares at infrared, optical and X-ray wavelengths, are sources of sub-Hz gravitational waves, and could emit very high energy neutrinos and cosmic rays. Emphasis will be placed on the feasibility and physics potential of future observations of neutrinos and other messengers from these diverse classes of emitters.

Facilitator
-Name：Shinobu Ozaki

2023.11.27-2023.12.3

November 28 Tue 10:00-11:30　太陽系小天体セミナー zoom　　　　　　　　　　　　　　

November 29 Wed 10:00-12:00　SOKENDAI Colloquium Large Seminar Room in Subaru Building and Zoom (hybrid)

November 29 Wed 15:30-16:30　NAOJ Science Colloquium Large Seminar Room in Subaru Building and Zoom (hybrid)

詳細は下記からご覧ください。

=============== November 　28 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：11月28日（火曜日）10時00分～11時30分
場所：zoom
講演者：土屋智恵

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

=============== November 　29 Wed===============

Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：November 29, 2023 10:00-12:00
Place：Large Seminar Room in Subaru Building and Zoom

Speaker: Seiya Imai
Affiliation: SOKENDAI 1st year (M1) (Supervisor: Masayuki Tanaka, Yusei Koyama, Kiyoto Yabe)
Title: Search for extreme emission line galaxies at 1<z<3 using Subaru/Hsc

Speaker: Rikuto Omae
Affiliation: SOKENDAI 55h year (D3) (Supervisor: Mami Machida, Masami Ouchi, Kazuhiro Hada)
Title: Probing the Magnetic Fields of Distant Galaxies to Unravel the Evolution of Galactic Magnetic Fields

Speaker: Yuta Tashima
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Mami Machida, Fumitaka Nakamura, Tomoya Takiwaki)
Title: Elucidation of Galactic Magnetic Field Structure by Pseudo-Observation Focusing on Depolarization

Facilitator
-Name：Matsuda, Graduate Student Affairs Unit

=============== November　29 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Nov. 29 (Wed.), 15:30-16:30
Place: the large seminar room / Zoom (hybrid)

Speaker: Yoko Oya
Affiliation: Kyoto University
Title: Physical Structures Traced by Chemical Diagnostics in Disk-Forming Regions of Young Low-Mass Protostellar Sources
Abstract:
To understand the origin of the Solar system, the physical/chemical evolution along the star/planet formation is a key issue. With the advent of ALMA, extensive observational studies have revealed that both the physical structure and the chemical composition drastically change during the disk formation around protostars. Furthermore, it has been found that molecular distributions are sensitive to changes in the physical conditions. Some kinds of molecular lines are therefore prospected to work as ‘molecular markers’ to selectively highlight particular structures of disk forming regions.
Specifically, sulfur-bearing species have empirically been good tracers; the kinematic structures of the circummultiple structure, the circumstellar disk, and the outflow lobes are traced by the OCS, H2CS, and SO emission, respectively, in a young low-mass protostellar source IRAS 16293-2422 Source A. The gas in its circummultiple structure was found to keep falling toward its periastron even beyond its centrifugal radius, which is often assumed to be the outer edge of a Keplerian disk.
Angular momentum of the gas is the essential topic to understand the structure formation. The chemical diagnostics with the aid of the molecular markers can be a helpful tool to tackle with the redistribution of the angular momentum among the disk/envelope and outflow structures. Conversely, detailed physical characterization is essential to elucidating the chemical evolution occurring there.

Facilitator
-Name: Masamitsu Mori

Comment: English

2023.11.20～2023.11.26

November 　21 Tue 10:00-11:30 太陽系小天体セミナー zoom　　　　　　　　　　　　　　

November 　21 Tue 14:30-15:30 ALMA-J seminar Seminar room in the Subaru building (院生セミナー室) / Zoom (hybrid)

November　22 Wed 10:30-12:00 SOKENDAI Colloquium Large Seminar Room in Subaru Building and Zoom

November　22 Wed 15:30-16:30 NAOJ Science Colloquium the large seminar room / Zoom (hybrid)

November 24 Fri 16:00-17:00 NAOJ Seminar Zoom/Large Seminar Room(hybrid)

詳細は下記からご覧ください。

=============== November 　21 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：11月21日（火曜日）10時00分～11時30分
場所：zoom
講演者：大島修（岡山理科大学）・藤井貢（藤井黒崎観測所）
タイトル：イオ周辺の中性ナトリウム雲の活動
Abstract：木星の衛星イオに関連したナトリウム雲の非常に活発な活動を観測したので報告する。藤井は、今年10月始めから口径13cm屈折望遠鏡にNaI D1
D2狭帯域フィルター（半値幅2.3nm）をかけて、木星の衛星イオの周辺を撮像観測している。イオからのナトリウム雲は、当初、軌道平面とは角度を持った方向へ噴出したものが、その後軌道平面方向に広がり、一部にねじれを持ったりしながら拡散しているように見える。一体どのような現象を見ているのか議論に供したい。

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

=============== November 　21 Tue===============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Nov 21 (Tue) 14:30-15:30
Place: Seminar room in the Subaru building (院生セミナー室) / Zoom (hybrid)
Speaker: Amanda Kepley (NRAO)

Title: Next Steps Towards Understanding Star Formation: Mapping Dense Gas in Nearby Galaxies
Abstract:
From both a theoretical and an observational perspective, dense gas plays an important role in star formation. Almost all theories of star formation have gas density as a key variable, while observations in the Milky Way and nearby galaxies suggest a close link between dense gas and star formation. Early unresolved observations of nearby galaxies suggested a simple relationship between the amount of dense gas and the amount of star formation in a galaxy. Recent resolved surveys of dense molecular gas in nearby galaxies, however, have shown that the dense gas fraction and the dense gas star formation efficiency ? ratio of the star formation rate to amount of dense gas ? varies within individual galaxies and among different galaxies. Unfortunately, the faintness of the primary dense gas tracers (HCN and HCO+) mean that these studies have been limited to small (5-10) samples of normal galaxies. In this talk, I will discuss recent observations that push the dense molecular gas observations in new directions. First, I will describe recent detections of dense molecular gas in the Local Group Dwarf starburst IC 10. Second, I will present early results from the Dense Extralactic GBT+Argus Survey (DEGAS). The goal of this survey is to map the dense molecular gas in the central 2arcmin of 36 nearby galaxies at moderate (10arcsec) resolution. I will conclude with thoughts on how a large mm cameras on single dish telescopes and more sensitive interferometers could further advance this important science.

Organizers: Gianni Cataldi, Hiroshi Nagai

=============== November　22 Wed==============

Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：November 22, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom

Speaker: Shotaro Tada
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Takayuki Kotani, Yutaka Hayano, Yosuke Minowa)
Title: InGaAs Detector Testing for JASMINE: Efforts to Minimize Readout Noise & Dark Current Measurement

Speaker: Ko Hosokawa
Affiliation: SOKENDAI 45h year (D3) (Supervisor: Takayuki Kotani, Yosuke Minowa, Yuka Fujii)
Title: Spectral Line Profile Measurement for Investigating Gas-giant Atmospheres

Facilitator
-Name：Matsuda, Graduate Student Affairs Unit

=============== November　22 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Nov. 22 (Wed.), 15:30-16:30
Place: the large seminar room / Zoom (hybrid)

Speaker: Jihye Hwang
Affiliation: KASI
Title: The distribution of magnetic field strengths in star-forming regions
Abstract:
“What is the role of magnetic fields for regulating star-forming processes?” It is a long- standing issue in star formation studies. To judge the exact role of magnetic fields in star-forming regions, it is necessary to estimate the magnetic field strengths of those regions.
However, previous studies have estimated a mean magnetic field strength in a whole star-forming region. I suggest a new application to estimate the distribution of magnetic field strengths in a star-forming region. I applied this towards three star-forming regions, the OMC-1 region, Mon
R2 and G28.34 using POL-2/SCUBA-2 on the James Clerk Maxwell Telescope.
In this talk, I will show the magnetic field strengths in those regions and discuss the relative importance between magnetic field, turbulence and gravity.

Facilitator
-Name: Doris Arzoumanian
Comment: English

=============== November　24 Fri==============

Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：November 24, 2023 16:00-17:00
Place：Zoom/Large Seminar Room (hybrid)

Speaker：Prof,Aya Ishihara
Affiliation：Chiba University

Title：ニュートリノを基軸とした宇宙のマルチメッセンジャー観測
Abstract:
高エネルギー宇宙ニュートリノは、宇宙のどこかで加速されている超高エネルギー宇宙線が天体内外の光や物質と相互作用することで生成される荷電パイオンの崩壊によって作られる。
同時につくられる中性パイオンの崩壊からはガンマ線が出るので、ニュートリノ天文学と言う時は通常光を使った観測と組み合わせ、マルチメッセンジャー天文学として統合的な宇宙理解を目指す。
特に、ニュートリノは天体内外の加速の現場からの情報を直接伝えてくれるので、粒子加速モデルの鍵となる情報をもたらすことが期待されている。また、ニュートリノのマルチメッセンジャー観測は、ダークマターや標準模型を超える物理に迫る観測をも可能とする。
このような高エネルギー宇宙ニュートリノの観測目指し南極点に建設されたのが世界初となる一立方キロメートルの容量を持つIceCubeニュートリノ望遠鏡だ。本講演ではIceCubeの完成から約10年で得られた成果を紹介し、その成果を踏まえた将来展望について議論する。

Facilitator
-Name：Okamoto, Takenori

2023/11/13~2023/11/19

November 　14 Tue 10:00-11:30 太陽系小天体セミナー zoom　　　　　　　　　　　　　　

November 　15 Wed 10:30-12:00 SOKENDAI Colloquium Large Seminar Room in Subaru Building and Zoom 　　

November　15 Wed 14:30-15:30 ALMA-J seminar Small seminar room in Subaru building (院生セミナー室) / Zoom (hybrid)

November　15 Wed 15:30-16:30 NAOJ Science Colloquium Zoom (full virtual style)

詳細は下記からご覧ください。

=============== November 　14 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：11月14日（火曜日）10時00分～11時30分
場所：zoom
講演者：野上長俊

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

=============== November 　15 Wed===============

Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：November 15, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom

Speaker: Yoshihiro Naito
Affiliation: SOKENDAI 2nd year (M2) (Supervisor: Hirohisa Hara. Ryoko Ishikawa, Joten Okamoto)
Title: Spectroscopic study of Alfvén waves in the upper chromosphere as an energy source of solar wind acceleration in coronal holes

Speaker: Yoshiaki Sato
Affiliation: SOKENDAI 2nd year (M2) (Supervisor: Noriyuki Narukage, Takashi Sekii, Masumi Shimojo)
Title: Evaluation of electron acceleration efficiency during solar flares using MHD+GCA Test-Particle simulation

Facilitator
-Name：Matsuda, Graduate Student Affairs Unit

=============== November　15 Wed==============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Nov 15th (Wed) 14:30-15:30
Place: Small seminar room in Subaru building (院生セミナー室) / Zoom (hybrid)
Speaker: Mengyuan Xiao
Affiliation: University of Geneva
Title: A new era of studying extremely dust-obscured massive galaxies in the early Universe with JWST and ALMA
Abstract:
Recent studies have unveiled the existence of extremely dust-obscured massive galaxies at z>3 and into the reionization epoch. This has significant implications for our understanding of early galaxy build-up and the cosmic star formation history. In this talk, I will discuss our recent findings on these galaxies with JWST FRESCO survey and GOODS-ALMA survey. In particular, I will present the advantages of JWST/spectroscopy in studying these galaxies. Based on the unprecedented imaging and spectroscopic data from the JWST FRESCO survey, we can systematically determine their spectroscopic redshifts, thus vastly improving constraints on their physical properties. In addition, I will show several extremely massive dusty galaxies at zspec > 5, that may challenge the current galaxy assembly models. I will discuss their ultra-massive properties, dust-obscured star formation rates, and the possibility of the existence of AGN. I will finish with some of our other recent discoveries and future plans for extremely dust-obscured massive galaxies.

Organizers: Gianni Cataldi , Hiroshi Nagai

=============== November　15 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Nov. 15 (Wed.), 15:30-16:30
Place: Zoom (full virtual style)

Speaker: Aya Bamba
Affiliation: The University of Tokyo
Title: X-ray study of supernova remnants, the origin of diversity in the universe

  • 多様性の源: 超新星残骸のX線研究 –
    Abstract:
    Supernova remnants (SNRs) supply thermal and kinetic energy, heavy elements, and high energy particles (cosmic rays) into the space, so they are the origin of diversity of the universe. Shocked plasma is heated up to 1-10 MK, and emits thermal X-rays with characteristic X-ray lines from heavy elements, thus X-ray observations are an ideal tool how SNRs play their role in the universe. In this talk, I will introduce several recent topics of SNR science – progenitor science and shock physics.
    Such a study needs excellent energy resolution in the X-ray band in order to resolve emission lines from minor elements and their Doppler motion. On this September, we succeeded to launch XRISM with H2A rocket.
    I also introduce how XRISM is launched and what XRISM will achieve on SNR science.

Facilitator
-Name: Hiroki Nagakura
Comment: English

2023.11.6~2023.11.12

　　

November 　6　 Mon 13:30-15:00 Solar and Space Plasma Seminar hybrid; Subaru Building / Insei Seminar Room or Zoom　　　　　　　　　　　　　　

November 　7　Tue　　9:00-12:00 　　

SOKENDAI Doctoral Thesis Preliminary Evaluation 総研大博士学位論文予備審査会
Lecture Room and Zoom&Large Seminar Room and Zoom　　　　　　　

November　7　Tue　10:00-11:30 　　太陽系小天体セミナー zoom

November　8　Wed　10:30-12:00　　 SOKENDAI Colloquium Large Seminar 　　　　　Room in Subaru Building and Zoom

November　10　Fri　16:00-17:00　　 NAOJ Seminar Zoom/Large Seminar Room(hybrid)

詳細は下記からご覧ください。

=============== November 　6 Mon===============

Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Scheduled
Date and time：6th November (Mon), 13:30-15:00
Place： hybrid; Subaru Building / Insei Seminar Room or Zoom
Speaker：Brigitte Schmieder
Affiliation：Observatoire de Paris, LESIA, France
Title：Solar jets observed by IRIS and high spatial resolution ground-based telescopes
Abstract：Solar jets have been observed over a large range of temperatures and wavelengths, from Hα for more than 50 years, to X-rays since the launch of the Yohkoh satellite in 1991. Several characteristics have been derived about their velocities, their rates of occurrence, and their relationship with CMEs. However, the initiation mechanism of jets, e.g. emerging flux, flux cancellation, or twist, is still debated. The high spatial resolution of IRIS and ground-based telescopes (SST,GST) allows us to make a step forward in understanding the relationship of cool and hot jets. Combining IRIS data with vector magnetograms we were able to study the magnetic environment favorable for the occurrence of jets. We searched for possible sites of reconnection by analyzing the magnetic topology.
We found that the magnetic reconnection site can be located at a null point in the corona as well as in a bald patch region forming a current sheet. The IRIS spectra provide evidence of bilateral flows at the reconnection site, due to a transfer of twist from a flux rope to the jet. We detected the presence of cool plasma and hot plasma during the jet formation, including ejections of blobs with speeds reaching super Alfvénic flows of the order of 300 km/s.

Facilitator
-Name：Takayoshi oba
Comment：in English

=============== November 　7 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：November 7, 2023　9:00～12:00

Place 1：Lecture Room and Zoom

Speaker：
9:00-9:40　Raiga Kashiwagi
Title：Instability and Evolution of Shocked Clouds Formed by Collisions between Filamentary Molecular Clouds

Speaker：
10:00-10:40　Yui Kasagi
Title：Unveiling Atmospheric Features of Faint Substellar Companions from High-Resolution Near-Infrared Spectra

Speaker：
11:00-11:40　Takaho Masai
Title：A Study on the Design of Receiver Optics and Waveguide Components Towards High-Performance (Sub)millimeter Wave Multibeam Receivers

Place 2：Large Seminar Room and Zoom

Speaker：
9:00-9:40　Rikuto Omae
Title：Probing the Magnetic Fields of Distant Galaxies to Unravel the Evolution of Galactic Magnetic Fields

Speaker：
10:00-10:40　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)

=============== November　7 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：11月7日（火曜日）10時00分～11時30分
場所：zoom
講演者：佐藤幹哉

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

=============== November　8 Wed==============

Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：November 8, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom

Speaker: Shunsuke Sasaki
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Tomoya Takiwaki, Mami Machida, Takashi Moriya)
Title: Developing “1D+” simulation of core-collapse supernovae

Speaker: Raiga Kashiwagi
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Kazunari Iwasaki, Tomoya Takiwaki, Doris Arzoumanian)
Title: Instability and Evolution of Shocked Clouds Formed by Collisions between Filamentary Molecular Clouds

Facilitator
-Name：Matsuda, Graduate Student Affairs Unit

=============== November　10 Fri==============

Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：November 10, 2023 16:00-17:00
Place：Zoom/Large Seminar Room (hybrid)

Speaker：Prof,Yasuhito Sekine
Affiliation：Earth-Life Science Institute

Title：Detection of phosphate in Enceladus’ ocean and comparative chemical evolution in the Solar System
Abstract:
Planetary habitability can be defined as a planetary-scale system that can develop and sustain ingredients of life—liquid water, organics, and energy—over geological time. In this regard, Enceladus possesses a habitable world beneath the icy shell. This moon has a global subsurface ocean interacting with a rocky core, and a wide variety of organic matter and chemical energy supported by hydrothermal activities are available. Among the major bioessential elements for Earth’s life, phosphorus (P) is usually the least abundant in natural aqueous systems and has been a limiting nutrient of primary productivity over Earth’s history. It has been unknown whether this essential element is available in Enceladus. Here we report the discovery of phosphate in ice grains emitted by Enceladus based on the analysis by Cassini’s Cosmic Dust Analyser. Our observational results are evidence that phosphorus is readily available in Enceladus’ ocean, with anomalously high concentrations–at least 100 times higher than Earth’s oceans. To understand the causative mechanism of the enrichment of phosphate, we performed hydrothermal experiments and geochemical modeling. We find that alkaline (pH ~10) and carbonate-rich aqueous environments are essential for the phosphate enrichment, where calcium phosphate minerals are thermodynamically unstable compared to calcium carbonate minerals. Such alkaline carbonate-rich aqueous environments are commonly achieved in icy ocean worlds beyond the CO2 snowline of the Solar System. Phosphate could have been also enriched in similar alkaline carbonate-rich aqueous environments on early Earth, where earliest life on Earth might have utilized phosphorus as components of its building materials.

Facilitator
-Name：Okamoto, Takenori