November 19 Tue 10:00-11:30
太陽系小天体セミナー (Solar System Minor Body Seminar)
Zoom
November 20 Wed 10:30-12:00
SOKENDAI Colloquium
hybrid; Large Seminar Room in Subaru Building and Zoom
November 20 Wed 14:30-15:30
SOKENDAI ALMA-J seminar
hybrid; Room 102 in ALMA Building and Zoom
November 20 Wed 15:30-16:30
NAOJ Science Colloquium
hybrid; Large Seminar Room in Subaru Building and Zoom
■This NAOJ seminar has been cancelled.(Nov.20.2024)
November 22 Fri 15:30-16:30
NAOJ Seminar
hybrid; Large Seminar Room in Subaru Building and Zoom
詳細は下記からご覧ください。
=============== November 19 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： 11月 19日（火曜日）10時～11時30分
場所：zoom
タイトル: 近況研究の話題持ち寄り
世話人の連絡先
-名前：渡部潤一
備考：zoomでの参加
=============== November 20 Wed===============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Scheduled
Date and time：November 20, 2024 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker：Yoshiaki Sato
Affiliation：SOKENDAI 3rd year (D1) (Supervisor: Noriyuki Narukage, Takashi Sekii, Masumi Shimojo)
Title：Electron acceleration around plasmoids and above-the-loop-top region in solar flares
Speaker：Tomokazu Kiyota
Affiliation：SOKENDAI 1st year (M1) (Supervisor: Masami Ouchi, Daisuke Iono, Masatoshi Imanishi)
Title：Exploring an Extremely Large Lya Source “Himiko” at z=6.6 with JWST and ALMA
Facilitator
-Name：Yoshihiro Naito
Comment：Language: English
===============November 20 Wed==============
Campus: Mitaka
Seminar: ALMA-J seminar
Regularly Scheduled/Sporadic: Wednesday
Date and time: November 20, 2024 (Wed), 14:30-15:30
Place: ALMA building #102 / Zoom (hybrid)
Speaker: Marianela Quirós-Rojas
Affiliation: INAOE
Title: ALMA follow-up of ∼3,000 red-Herschel galaxies: the nature of extreme submillimeter galaxies.
Abstract: Understanding the physical properties of Submillimeter Galaxies (SMGs), as well as their formation and evolution within the large-scale structure of the Universe, is a challenging task even these days. These galaxies, which have extreme infrared luminosities (L$_IR$>10^{12} L$_{\odot}$) and intense star formation rates (SFR>100 M$_{\odot}$/yr), are known to contribute significantly to the cosmic star formation history at z>2.
In this work, we present the analysis of over 3,000 red-Herschel sources (𝑆_250𝜇m < 𝑆_350𝜇m < 𝑆_500𝜇m ) using public data from the ALMA archive and the Herschel-ATLAS survey. This represents the largest sample of red-Herschel sources with interferometric follow-up observations to date.
The high ALMA angular resolution and sensitivity allow us to classify the sample into individual sources, potential lenses and/or close mergers, and multiple systems. Some of these multiple systems are likely galaxy overdensities at the same redshifts tracing high-redshift galaxy proto-clusters.
We performed spectral energy distribution (SED) fits for all the sources, combining the ALMA 1.3 mm fluxes and the optimized Herschel/SPIRE photometry (extracted through a deblending technique). This allows us to derive different physical properties (e.g. redshift distribution, LIR, SFR, gas/dust masses, etc) and characterize the extreme nature of this population. The main results from this large survey and recent follow-ups with the VLA and LMT will be presented in this talk.
Facilitator: Bunyo Hatsukade and Masumi Shimojo
===============November 20 Wed==============
Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2024 November 20 (Wed.), 15:30-16:30 JST
Place: The large seminar room / Zoom (hybrid)
Speaker: Tommaso Grassi
Affiliation: Max Planck for Extraterrestrial Physics
Title: Numerical Challenges in Computational Astrochemistry
Abstract: Astrophysical numerical models encounter substantial computational challenges when integrating complex, time-dependent chemistry with physical processes. To address these issues, I will present the use of autoencoders for the dimensionality reduction of chemical networks, enabling efficient solutions with standard ODE solvers while preserving key network features. Additionally, I will discuss the application of interpretable machine learning techniques to connect synthetic spectra with model parameters, facilitating the assessment of information retention in observational data.
Facilitator
-Name: Nanase Harada
Comment: English
===============November 22 Fri==============
■This NAOJ seminar has been cancelled.(Nov.20.2024)
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：November 22, 2024 15:30-16:30
Place：Zoom/Large Seminar Room (hybrid)
Speaker：Dr. Sho Fujibayashi
Affiliation：Tohoku University
Title：Powerful supernovae from collapses of rotating massive stars
Abstract: Massive stars, with more than about ten times the mass of the Sun, eventually become gravitationally unstable and begin to collapse. Some of these collapsing stars explode as supernovae, which then leave behind neutron stars. However, in cases where the collapsing core of the star is too compact, the explosion can fail, leading to the formation of a black hole instead.
When the star rotates rapidly, the stellar envelope can form a disk around this new black hole. This black hole-disk system may release energy, and it is thought to be a key driver of gamma-ray bursts — intense, brief flashes of gamma rays from space. Some gamma-ray bursts are followed by unusually powerful supernovae, with energy about ten times higher than typical supernovae. How this large amount of energy and radioactive nickel, which makes these supernovae so bright, are produced is still a mystery.
Over recent decades, it has been suggested that outflows from the disk around the black hole might explain these energetic supernovae. With advances in computer simulations, we can now model complex processes, including fluid dynamics, neutrino interactions, and changing spacetime, to test this idea. My simulations show that the disk outflows in these “collapsar” systems can indeed produce the powerful explosion energy and the large amount of nickel seen in these exceptional supernovae.
Facilitator
-Name：Yasunori Hori