2023.12.11-2023.12.17

December 12 Tue 10:00-11:30 太陽系小天体セミナー
Zoom


December  13 Wed 10:30-12:00 SOKENDAI Colloquium
Large Seminar Room in Subaru Building and Zoom (hybrid)


December  13 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。

=============== December  12 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12日(火曜日)10時00分~11時30分
場所:zoom
講演者:古荘玲子

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  13 wed===============

Campus:Mitaka
Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:December 13, 2023 10:30-12:00
Place:Large Seminar Room in Subaru Building and Zoom

Speaker: Shun Hatano
Affiliation: SOKENDAI 2nd year (M2) (Supervisor: Masami Ouchi, Yusei Koyama, Takashi Moriya)
Title: Supermassive black holes at high redshifts explored with James Webb Space Telescope

Speaker: Shun Ishigami
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Hirohisa Hara, Yukio Katsukawa, Masahito Kubo)
Title: Estimating the filling factor of coronal loops using EUV spectroscopic data

Facilitator
-Name:Matsuda, Graduate Student Affairs Unit

=============== December  13 wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Dec. 13 (Wed.), 15:30-16:30
Place: the large seminar room / Zoom (hybrid)

Speaker: Kensuke Kakiuchi
Affiliation: The University of Tokyo
Title: MHD Simulation of The Inner Galaxy with Radiative Cooling and Heating
Abstract:
Magnetic field is supposed to play a key role in the interstellar gas of the Galactic Center region (inner Galactic Bulge region).
Observations show that the strength of the magnetic field within the central few hundred parsecs of the Galaxy is stronger than in the Galactic disk region, and its magnetic energy is comparable poor even surpasses the thermal and kinetic energy of the interstellar gas.
Therefore, it is essential to study the role of the magnetic field to understand the behavior of the interstellar gas in the Galactic center region.
In this talk, we will present the results of 3D global magnetohydrodynamical simulations in the Galactic center region. A notable distinction from previous simulations is the inclusion of radiative cooling and heating effects. We found the formation of a mid-latitude low-plasma beta zone (dominated by magnetic field pressure), which would not have appeared in the model without radiative heating and cooling. While the thermal energy of the interstellar gas is lost because of radiative heating and cooling effects, the magnetic energy is independent of this direct effect and can contribute to the thickness that supports the interstellar gas clouds above the Galactic plane.In fact, it is difficult to explain the thickness of gas clouds in the Galactic center using only gas pressure scale heights, suggesting that the contribution of the magnetic field is important as an interpretation of this thickness.

Facilitator
-Name: Doris Arzoumanian

Comment: English

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

2023.10.30-2023.11.5


October 31 Tue   10:00-11:30  太陽系小天体セミナー    Zoom
                    


October 31 Tue  15:30-16:30    NAOJ Seminar 
                   Zoom/Large Seminar Room (hybrid)             


November 1 Wed 10:30-12:00   SOKENDAI Colloquium 
            Large Seminar Room in Subaru Building and Zoom


November 1 Wed 14:30-15:30   ALMA-J seminar  
            hybrid (ROOM102 in ALMA building and ZOOM)


November 1 Wed 15:30-16:30   NAOJ Science Colloquium  
              the rinkoh seminar room / Zoom (hybrid)


November 2 Thu 11:00-12:00   Tea Talk       Zoom

詳細は下記からご覧ください。

=============== October  31 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31日(火曜日)10時00分~11時30分
場所:zoom
講演者:藤井大地

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  31 Tue==============

Campus:Mitaka
Seminar:NAOJ Seminar
Regularly Scheduled/Sporadic:Regular
Date and time:October 31, 2023 15:30-16:30
Place:Zoom/Large Seminar Room (hybrid)

Speaker:Ruobing Dong, PhD
Affiliation:University of Victoria

Title:Observational Planet Formation
Abstract:
It is hard to see a plane cruising at 10 km during daytime, as the plane is
tiny and faint on the sky. But, if we can see the contrail tailed behind the
plane, we know where the plane is. Now, astronomers are applying the same
principle to study how planets form, by detecting and charactering the
structures baby planets produce in their birth cradles – protoplanetary
disks. This is a new field largely driven by discoveries made by some of the
largest and most advanced telescopes ever built. I will introduce the
current status of the field, and highlight some of the latest developments
as well as unsolved problems.

Facilitator
-Name:Prof. Nomura, Hideko

=============== November 1 Wed==============

Campus:Mitaka
Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:November 1, 2023 10:30-12:00
Place:Large Seminar Room in Subaru Building and Zoom

Speaker: Ryota Hatami
Affiliation: SOKENDAI 1st year (M1) (Supervisor: Nozomu Tominaga, Tomoya Takiwaki, Koh Takahashi)
Title: Synthesis of Sc, Ti, and V in core-collapse Supernovae toward constraining explosion mechanism

Speaker: Masato Sato
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Nozomu Tominaga, Tomoya Takiwaki, Takashi Moriya)
Title: Exploring electron-capture supernovae in past observations

Facilitator
-Name:Matsuda, Graduate Student Affairs Unit

=============== November 1 Wed==============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Nov 1st (Wed) 14:30-15:30
Place: hybrid (ROOM102 in ALMA building and ZOOM)
Speaker: Ceci Xue
Affiliation: MIT
Title: Molecular Spectra Diagnostics with a Bayesian MCMC Approach
Abstract:
The recent improvement in receiver technology within modern facilities has enabled us to efficiently perform wide-band and high-sensitive molecular line surveys. To better extract the information from these wide-band spectral data, we introduce a molecular signal diagnostic tool coupling a non-LTE radiative transfer model and a Markov Chain Monte Carlo (MCMC) approach. Based on RADEX (van der Tak et al. 2007), our tool features novel implementations to support multiple components along the line of sight and allow Bayesian inference about physical characteristics. In contrast to a canonical least-squares fit approach, MCMC analyses allow a more efficient exploration of the physical parameter space and provide access to the parameter’s probability distribution, which can be used to characterize the confidence intervals and covariances between parameters. In this talk, following a brief introduction to Bayesian statistics, we will present a case study demonstrating the analysis of molecular line observations from ALMA using this tool. Specifically, we will share the first detection and mapping of the Class I methanol maser at 84 GHz toward the north region of Sagittarius B2 molecular cloud. We resolved the regions where the maser emission originates and assessed their observed spectral profiles respectively. The results suggest a chained two-component model for explaining the intense methanol Class I maser emission toward a region with weak continuum background radiation. In addition, our diagnostic tool will be applied to the spectral line survey, GOTHAM, which has a total bandwidth of 25GHz, to conduct the full chemical census toward the TMC-1 dark cloud.

Organizers: Gianni Cataldi, Hiroshi Nagai

=============== November 1 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Nov. 1 (Wed.), 15:30-16:30
Place: the rinkoh seminar room / Zoom (hybrid)

Speaker: Biagio De Simone
Affiliation: UNISA
Title: An Optical Gamma-Ray Burst catalogue with Measured Redshift: Data Release of 533 Gamma-Ray Bursts and colour evolution
Abstract:
Gamma-Ray Bursts (GRBs) are incredibly energetic cosmic phenomena observed across a wide range of wavelengths, including gamma-ray and optical frequencies, and occasionally even in radio waves. They allow extending the Hubble diagram and the cosmological analysis up to redshift z=9.4, much further than Supernovae Ia (z=2.26).
We therefore present a compilation of 533 optical lightcurves (LCs) of all GRBs with measured redshifts, detected mainly by Swift and 418 ground-based telescopes from February 28, 1997, to April 14, 2023. This catalogue is the largest optical repository of GRB LCs with redshifts to date, with 64615 photometric data points, including upper limits. Our user-friendly web tool, grbLC, allows the acquisition of GRB LCs, including information on the position, redshift, and a Gamma-ray Coordinates Network (GCN) crawler that can be used to collect data by gathering magnitudes from the GCNs. The web tool also includes a package for uniformly investigating colour evolution. We have crafted a procedure to distinguish between GRBs in our sample, which undergo colour evolution, and GRBs for which no colour evolution is present. We compared our results with the literature. This web-based archive is the first step towards unifying several community efforts to gather optical LCs by providing a unified format and repository for the optical catalogue. This catalogue will enable population studies by providing LCs with better coverage since we have gathered data from different ground-based locations, resulting in fewer gaps in the LCs and representing crucial support for the LC reconstructions analysis.

Speaker: Chanoul Seo
Affiliation: NAOJ
Title: Impact of Magma Redox States on Super-Earth Atmospheres:
Unveiling the Connection with Atmospheric Composition
Abstract:
Most exoplanets with radii larger than ~1.6Earth mass are more inflated than bare-rock planets with the same mass, indicating a substantial amount of volatile. While it is hard to constrain the origin of the volatiles or the planet’s bulk composition only from the mass-radius relation, the spectral characterization of their atmospheres is expected to solve this degeneracy. Previous models pointed out that the interaction between the accreted volatile and the likely molten rock (i.e., magma) beneath the atmosphere would affect the atmospheric composition significantly. However, existing models do not clarify the dependence of the atmospheric compositions with major spectral fingerprints on the observable planetary parameters. In this work, we explore the possible range of H, O, and C in the atmosphere of exoplanets as a function of observable planetary parameters (mass, radius, equilibrium temperature) using a simple chemical equilibrium model. Consistent with the previous work, we show that the water fraction in contact with magma ocean is the order of 10^-2~10^-1 if the dry planetary core accretes the nebula gas. Due to the difference in solubility of H-bearing and C-bearing species in molten rock, C/H shows an increase of ×3~10^2. The low values correspond to H2-rich atmospheres while the high values (the order of magnitude difference) correspond to the thin atmosphere with pressure <10^3 bar. Therefore, the C/O remains relatively low in most of the parameter range considered, below one-tenth of the nebula gas value if the atmospheric H2O fraction is over five percent. These trends provide a clue to verify or falsify the formation scenario of super-Earth/sub-Neptune from atmospheric compositions.

Facilitator
-Name: Maria Giovanna Dainotti
Comment: English

=============== November 2 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:11/2(木)11:00~12:00
場所:Zoom(のみ)
Speaker:Hannah Harris
Title:
International Scientific Cooperation with North Korea: from Ancient Astronomy to Today

Abstract:
The Korean Peninsula is home to an ancient and unique tradition in astronomy. Beginning with the prehistoric Stone Age and blossoming over the last two thousand years, astronomy is deeply enmeshed in Korean culture. It is unsurprising that North Korea, just like its neighbor to the South, continued this scientfic tradition. Yet astronomy and science in North Korea is still relatively unknown and understudied. Today, North Korean scientists are active participants in the international scientific community across many fields and disciplines. This talk presents the history and future prospects for international scientific cooperation with North Korea with an emphasis on astronomy.

Short bio:
Hannah Harris is a Canadian-American science communicator, researcher, and a current Marie Sklodowska-Curie Fellow with the International Atomic Energy Agency (IAEA). She has a Bachelor’s degree in Astrophysics from Wellesley College (USA) and researched spinning black holes at the MIT Center for Theoretical Physics and the Gravitational Physics Group at Cardiff University (Wales, UK). Recently, she finished a dual-degree masters program between Russia and the United States, where she studied nuclear physics, nuclear energy, and nuclear weapons, as well as international relations. Her thesis focused on scientific research in North Korea and the possibilities for nuclear risk reduction through peaceful scientific cooperation. Since 2014, she has collaborated with the IAU on a variety of space policy and outreach projects and served as the project manager for the “Inclusive Astronomy” programme during the IAU100 centennial celebrations in 2019.

世話人の連絡先:
-名前:藤田登起子
参加方法:Zoom