Oct 10 Tue 10:00-11:30 太陽系小天体セミナー Zoom
Oct 11 Wed 13:30-15:00 Solar and Space Plasma Seminar hybrid; Subaru Building / Insei Seminar Room or Zoom
Oct 11 Wed 14:00-15:00 Tea Talk 輪講室（＋Zoom）
Oct 11 Wed 14:30-15:30 ALMA-J seminar hybrid (ROOM102 in ALMA building and ZOOM)
Oct 11 Wed 15:30-16:30 NAOJ Science Colloquium Zoom / the large seminar room (hybrid)
Oct 13 Fri 16:00-17:00 NAOJ Seminar zoom/ Large seminar room in Subaru Building
詳細は以下をご覧下さい。
=============== October 10 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10日（火曜日）10時00分～11時30分
場所：zoom
講演者：秋澤宏樹
Abstract：『COMETS III』より、著者による先行公開されている２つの章、
「彗星大気の化学」
https://www.research.ed.ac.uk/en/publications/chemistry-of-comet-atmospheres
「遠隔観測による彗星核の物理・表面特性」
https://arxiv.org/abs/2304.09309
の内容を紹介したいと思います。
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
=============== October 11 Wed===============
Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Scheduled
Date and time：11th Oct (Wed), 13:30-15:00
Place： hybrid; Subaru Building / Insei Seminar Room or Zoom
Speaker： Stanislav Gunar
Affiliation：Astronomical Institute of the Czech Academy of Sciences
Title：What is important for robust inversions of spectroscopic observations of chromospheric and coronal structures?
Abstract：In this presentation, we will discuss what is hidden behind the term “robust spectroscopic inversions” and what we need to achieve them. We will focus on the use of UV spectral data, such as the Lyman line series and the Mg II h&k lines.
There are several necessary ingredients needed to produce high-fidelity spectroscopic inversions. The first is high-resolution multi-wavelength observations. The second are realistic radiative transfer models encompassing dominant processes forming the observed spectra. The third component is sophisticated inversion methods that allow us to find a realistic fit between the observed and synthetic spectra. And there is another necessary component – a good understanding of all important boundary conditions.
We will demonstrate the importance of boundary conditions on the example of the so-called incident radiation. This is the radiation coming from the solar surface, which illuminates chromospheric and coronal structures, such as prominences or spicules. We will show that variations in this boundary condition have a strong impact on the shape and intensity of Lyman lines and the Mg II h&k lines. This impact is then responsible for significantly different outcomes of spectroscopic inversions.
Facilitator
Name：Takayoshi oba
Comment：in English
=============== October 11 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：10/11（水）14：00～15：00
場所：輪講室（＋Zoom）
講演者：渡部 潤一
所属：天文情報センター
タイトル：APRIM2023の顚末記
世話人の名前：藤田登起子
=============== October 11 Wed===============
Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Oct 11th (Wed) 14:30-15:30
Place: hybrid (ROOM102 in ALMA building and ZOOM)
Speaker: Tetsu Kitayama
Affiliation: Toho University
Title: High-resolution measurements of the Sunyaev-Zel’dovich effect toward galaxy clusters
Abstract:
The Sunyaev-Zel’dovich effect (SZE) provides a unique probe of cosmic plasma up to high redshifts. We first review briefly the progress of high-resolution SZE observations over the past two decades. We then present the measurements made by the Atacama Large Millimeter/submillimeter Array (ALMA); we have obtained SZE images toward four galaxy clusters with 5″ resolution, while retaining extended signals out to 40″. We also discuss implications of these results on the evolution of galaxy clusters as well as prospects for further SZE measurements.
=============== October 11 Wed===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday Date and time：2023 Oct. 11, 15:30-16:30
Place：Zoom / the large seminar room (hybrid)
Speaker：Daichi Kashino
Affiliation：NAOJ
Title：Witnessing Galaxies Reionizing the Intergalactic Medium with JWST
Abstract：
Cosmic reionization is the last major phase transition of the universe, occurring in the first billion years after the Big Bang.
Understanding this process is one of the pivotal goals in modern astrophysics. The commissioning of JWST heralded a new era in investigating the roles of galaxies in reionizing the intergalactic medium, thanks to its unprecedented high sensitivity and dispersing power in near infrared.
In the presentation, I will present early results from our ongoing EIGER (Emission-line galaxies and Intergalactic Gas in the Epoch of
Reionization) survey, a JWST/NIRCam WFSS campaign in the fields of luminous z>6 quasars. The existence of these background quasars enables us to determine the ionization condition along their lines of sight from analysis of the high signal-to-noise quasar spectra. The primary objective of the project is to characterize the cross correlation between galaxies (as pinpointed by JWST) and the IGM conditions during the tail end of the epoch of reionization. In the first quasar field, we confirmed roughly 150 [OIII]5008-emitting galaxies over the redshift range of z=5.3–6.9. Through analyzing the distribution of these galaxies and the transmission spectrum of this corresponding quasar, we identified individual spatial coincidence between the groups of galaxies and highly ionized regions, as well as a mean excess IGM transmission in both Lyman-alpha and Lyman-beta around ~6 cMpc away from the galaxies at z~6. This is interpreted as direct evidence of local reionization by galaxies — indicating that we are witnessing galaxies reionizing the surrounding IGM. I may also showcase further preliminary results from other quasar fields currently being analyzed.
Facilitator
Name：Haruka Kusakabe
Comment：English
=============== October 13 Fri===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regularly Scheduled Date and time：2023 Oct 13, 16:00-17:00
Place：zoom/ Large seminar room in Subaru Building
Speaker: Cristian Eduard Rusu, PhD
Affiliation: Axelspace Corporation
Title: Opportunities and Challenges for Space Observations with Commercial Satellites
Abstract：Over the past decade, the number of satellites launched into orbit for commercial
purposes has increased exponentially. Nonetheless, these have had virtually no usage for
astronomical observations, due to the still prohibitive cost of launching large mirrors and
achieving scientific-level tolerances. In recent years however, governments as well as private
companies have become interested in Space Situation Awareness, or gaining insights from
optical monitoring from space of artificial satellites and space debris as faint as the 14th magnitude.
This renewed interest in space observations has the potential of reducing the cost of dedicated
astronomical satellites and bringing them within the reach of commercial companies.
I will explore these topics as experienced from the point of view of Axelspace, a Japanese commercial
satellite manufacturer and provider of satellite imagery.
Facilitator
-Name：Moriya, Takashi