カテゴリー: 科学研究部コロキウム

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June 11 Tue 10:00-11:30
太陽系小天体セミナー (Solar System Minor Body Seminar)
Zoom

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

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June 12 Wed 15:30-16:30
NAOJ Science Colloquium
hybrid; Large Seminar Room in Subaru Building and Zoom

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June 13 Thu 14:30-15:30
ALMA-J seminar
hybrid; Room 102 in ALMA Building and Zoom

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June 14 Fri 13:30-14:30
ATCセミナー
hybrid; Large Seminar Room in Subaru Building and Zoom

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June 14 Fri 15:30-16:30
NAOJ Seminar
hybrid; Large Seminar Room in Subaru Building and Zoom

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June 14 Fri 15:30-17:00
Solar and Space Plasma Seminar
hybrid; Insei Seminar Room in Subaru Building and Zoom

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詳細は下記からご覧ください。

=============== June 11 Tue===============

キャンパス：三鷹
セミナー名：太陽系小天体セミナー (Solar System Minor Body Seminar)
定例・臨時の別：定例
日時：　6月　11日（火曜日）10時00分～11時30分
場所：zoom
講演者：和田空大
所属: 東京大学
タイトル: 研究紹介

世話人の連絡先
-名前：渡部潤一

備考：zoomでの参加

=============== June 12 Wed===============

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

Speaker：Takumi Kakimoto
Affiliation：SOKENDAI 3rd year (D1) (Supervisor: Masayuki Tanaka, Daisuke Iono, Kiyoto Yabe)
Title：The role of the environment in quenching of massive galaxies at high redshifts

Speaker：Kazuki Watanabe
Affiliation：SOKENDAI 2nd year (M2) (Supervisor: Tai Oshima, Yoshinori Uzawa, Takafumi Kojima)
Title：Development of a sub-THz MKID Camera for Deep Space Observation

Facilitator
-Name：Yoshiaki Sato

Comment：Language: English

===============June 12 Wed==============

Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2024 June 12 (Wed.), 15:30-16:30 JST
Place: the large seminar room / Zoom (hybrid)

Speaker: Mehrnoosh Tahani
Affiliation: Stanford University
Title: Galactic Structure and Evolution: What 3D Magnetic Field Observations Are Revealing
Abstract:
Recent observations have significantly advanced our understanding of the three-dimensional (3D) structure and evolution of the interstellar medium (ISM). To fully comprehend ISM evolution, however, it is necessary to study interstellar magnetic fields, which play a pivotal role in the evolution of the galaxy and the formation of stars. Despite their importance, our understanding of magnetic fields in the ISM is limited due to significant challenges in observing them in 3D. In this talk, I will briefly discuss how we overcame the challenges in determining the 3D magnetic fields associated with giant molecular clouds. These 3D fields enabled us to propose step-by-step scenarios to explain the formation of these clouds, revealing previously undiscovered interstellar structure. Our approach involves a novel technique based on Faraday rotation measurements to detect the line- of-sight component of magnetic fields. We then integrate these line-of-sight measurements with plane-of-sky magnetic field observations to examine the 3D magnetic field morphology associated with the clouds. Finally, we employ Galactic magnetic field models to reconstruct the complete 3D magnetic field morphologies of these clouds, including their previously unknown direction. These 3D studies provide novel constraints on theories for the formation and evolution of star-forming clouds.

Facilitator
-Name: Nanase Harada

Comment: English

===============June 13 Thu==============

Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: 2024 June 13 (Thursday), 14:30-15:30 JST
Place: Room 102 in ALMA building / Zoom (hybrid)
Speaker: Nimesh Patel
Affiliation: Harvard-Smithsonian Center for Astrophysics

Title: Chemical Evolution from AGB stars to Planetary Nebulae: A spectral-line survey of the Egg Nebula (CRL 2688)
Abstract:
Carbon-rich stars on the asymptotic giant branch (AGB) are major sources of gas and dust in the interstellar medium. AGB stars remain
in this stage for 1 to 10 Myrs, and have typical masses of 1–8 Msun and mass loss rates of 10^(−7) to 10^(−4) Msun/yr. During the
brief (∼1000 yr) period in the evolution from the AGB to Planetary Nebula (PN) there is a dramatic change in the morphology from nearly
spherical symmetry to bipolar, quadrupolar and more complex structures.
Because of the brief duration of this Proto-Planetary Nebula (PPN) phase and the poor angular resolution of most prior molecular line
observations (>= 15″– 20″), the physical mechanisms governing the AGB -> PPN -> PN transition and the accompanying chemical processes
are poorly understood.

Using the Submillimeter Array (SMA), we have previously carried out spectral-line surveys of CRL 618, NGC 7027, and IRC+10216. In this
talk, I will present preliminary results from a spectral-line survey of CRL2688 (Egg Nebula), which is a well known PPN with multiple
outflows and shell-like structures discovered in HST images.
Together, these unbiased surveys of the 4 prototypical carbon rich objects which span the evolutionary sequence from the AGB to fully
formed planetary nebula — IRC+10216 (AGB), CRL 2688 (early PPN), CRL 618 (PPN) and NGC 7027 (PN) — have the potential of unravelling
the physical and chemical evolution of circumstellar envelopes from AGB to PN.

The SMA line survey of CRL 2688 covers the frequency range of 224–266 GHz, with an rms noise level of 100~150 mJy/beam in 1 km/s
wide channels. About 130 lines are detected in the 42 GHz coverage; all the detected lines have been identified. Lines of silicon
bearing species such as SiCC and SiS are much weaker (compared to those seen in IRC+10216). Several lines show morphological features
corresponding to the multiple outflows in this source (HCN, CS), and the disk like structure (CH3CN,SiS). The channel maps show an
S-shaped morphology for the bipolar lobes in CS and HCN, clear indication of a precessing/wobbling jet or two jets with different
axes. It is interesting to see Si bearing molecules, and weak lines of c-C3H2 in CRL 2688, whereas this molecule is one of the most
abundant in CRL 618 (with more than 150 lines in that survey). Maps of a few of the trace species — the first images obtained for most
of these — reveal diverse angular distributions, allowing us to distinguish the different regions in which each species is present
in this complex source.

Facilitator
-Name: Pei-Ying Hsieh

===============June 14 Fri==============

キャンパス：三鷹
セミナー名：ATCセミナー
定例・臨時の別：臨時
日時：6月14日（金曜日）13時30分～14時30分
場所：大セミナー室 + Zoom

講演者： Pradip Gatkine 氏
所属： UCLA
タイトル：Astronomical instruments on a chip – Getting ready for the next-generation telescopes

Abstract：
Astrophotonics is the application of versatile photonic technologies to channel, manipulate, and disperse guided light from one or more telescopes to achieve scientific objectives in astronomy in an efficient and cost-effective way. The photonic platform of guided light in fibers and waveguides has opened the doors to next-generation instrumentation for both ground- and space-based telescopes in optical and near/mid-IR bands, particularly for the large and extremely large telescopes (ELTs). Utilizing the photonic advantage for astronomical spectroscopy is a promising approach to massively miniaturize the next generation of spectrometers for large ground- and space-based telescopes. In this talk, I will discuss some of the recent results from our efforts to design and fabricate high-throughput on-chip spectrometers based on Arrayed Waveguide Gratings (AWG). These devices are ideally suited for capturing the AO-corrected light and enabling exciting science cases, such as measuring exoplanet masses and characterizing exoplanet atmospheres. I will also discuss specific approaches to make this technology science-ready for the ELT era.

世話人の連絡先
-名前：永井　誠

備考：英語での講演。

===============June 14 Fri===============

Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：June 14, 2024 15:30-16:30
Place：Zoom/Large Seminar Room (hybrid)

Speaker：Dr. Nimesh Patel
Affiliation：Center for Astrophysics/ Harvard University

Title：Building the Next Generation Event Horizon Telescope

Abstract:The next-generation Event Horizon Telescope (ngEHT) will be a transformative upgrade to the EHT, that will allow us to create time-lapse movies of supermassive black holes (SMBHs) at event horizon scales. By enhancing the angular resolution, dynamic range, and improved temporal coverage, the ngEHT promises a new era of discovery in black hole science, allowing us to study strong-field gravity features predicted by General Relativity (GR), active accretion, and relativistic jet launching processes. The ngEHT program aims to achieve these goals by adding four 10m-class submillimeter dishes at new geographic locations around the globe, for improved spatial frequency coverage. Several of the existing EHT stations will have upgraded receivers and fore-optics for simultaneous multifrequency observations (86, 230 and 345 GHz), and new backends and data recorders with significantly higher data rates (up to 320 Gb/s). The ngEHT will allow longer duration high cadence observations allowing creation of movies of black holes and jets. This talk will describe the ngEHT’s technical plans, design considerations, station siting, and the project’s timeline.

Facilitator
-Name：Takashi Moriya

=============== June 14 Fri===============

Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Sporadic
Date and time：14 June (Fri), 15:30-17:00
Place： Insei Seminar Room and Zoom

Speaker：Dr. Alexei Pevtsov
Affiliation：National Solar Observatory
Title： Integrated Synoptic Program at the US National Solar Observatory and ngGONG

Abstract：

Providing the background synoptic observations to characterize the variable solar activity and operating ground-based facilities to enable
such long-term observations are two key aspects of the US National Solar Observatory (NSO) mission, which are entrusted to NSO’s Integrated
Synoptic Program (NISP). The program operates two facilities: Global Oscillation Network Group (GONG) and Synoptic Optical Long‐term
Investigations of the Sun (SOLIS). Data from these facilities are provided to research and space weather operation communities. This talk
will overview the Program activities, provide status of GONG and SOLIS facilities, and discuss their future replacement – a ground-based
network of robotic instruments provisionally called next generation GONG (ngGONG).

Facilitator
-Name：Akiko Tei

Comment：Japanese (Slides will be in English)