September 5 Tue 10:00-11:30 太陽系小天体セミナー zoom
詳細は下記からご覧ください。
=============== September 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：9月5日（火曜日）10時00分～11時30分
場所：zoom
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
投稿者: writer
2023.8.28-2023.9.3
August 30 Wed 13:30-15:00 Solar and Space Plasma Seminar
hybrid; Central Building (North)310 or Zoom
August 30 Wed 14:30-15:30 ALMA-J seminar
Zoom / ALMA building #102 (hybrid)
詳細は下記からご覧ください。
=============== August 30 Wed===============
Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Scheduled
Date and time：Aug 30th (Wed), 13:30-15:00
Place： hybrid; Central Building (North) / 310 or Zoom
Speaker：Dr. Masahito Kubo
Affiliation：NAOJ
Title：Comparison of polar magnetic fields derived from MILOS and MERLIN inversions for Hinode/SOT-SP data
Abstract：The detailed investigation of the polar magnetic field and its time evolution is one of the major achievements of Hinode. Precise measurements of the polar magnetic field are essential for understanding the solar cycle, and they provide important constraints for identifying the source regions of the solar wind. The Spectropolarimeter (SP) of the Solar Optical Telescope (SOT) on board Hinode has been the instrument best suited to make such measurements. In this study, we compare SOT-SP data for the polar regions as processed using two representative Milne-Eddington inversion codes, MILOS and MERLIN. These codes are applied to the same level-1 SOT/SP data, and the same disambiguation algorithm is used on the maps that go through the two inversions. We find that the MERLIN inversion tends to give the radial magnetic flux density (the magnetic flux density with respect to the local vertical) that is about 20% larger than the MILOS inversion. The somewhat higher radial magnetic flux density from MERLIN appears to be common to the polar magnetic fields observed at different phases of the solar cycle. We attribute the difference in the radial magnetic flux density to different filling factors adopted by the two inversions, based on different assumptions of the scattered light profiles. The relationship between the radial magnetic flux density and the magnetic filling factor could be more complex in the polar (limb) observations due to the possible contributions of the transverse magnetic field component that may affect the estimated radial magnetic flux density.
Facilitator
-Name：Takayoshi oba
-Comment：in English
=============== August 30 Wed==============
Campus: Mitaka
Seminar: ALMA-J seminar
Regularly Scheduled/Sporadic: Every Wednesday
Date and time: August 30, 2023 (Wed), 14:30-15:30
Place: ALMA building #102 / Zoom (hybrid)
Speaker: Jan-Willem Steeb
Affiliation: National Radio Astronomy Observatory
Title: AstroHACK: Holography Antenna Commissioning Kit
Abstract: Correcting the surface of a dish antenna by adjusting the panels can significantly improve the dish’s performance. For instance, the VLA panel adjustments completed in 2000 more than doubled the high-frequency sensitivity of the VLA dishes. The software presently utilized by ALMA and VLA is written in Fortran and is becoming challenging to maintain. Consequently, the CASA team is developing AstroHACK, which generates antenna aperture images and calculates antenna panel adjustment corrections from calibrated holography measurement sets. AstroHACK is the first non-prototype software package developed using the Python-based VIPER (Visibility and Image Parallel Execution Reduction) Framework, previously known as the CASA Next Generation Infrastructure Software Framework. This framework was designed to meet the requirements of the ngVLA and the ALMA Wideband Sensitivity upgrade. In this seminar, I will provide an overview of the VIPER Framework and the functionalities of AstroHACK, followed by a live demonstration.
2023.8.21-2023.8.27
August 21 Mon 14:30-15:30 ALMA-J seminar Zoom / ALMA building #102 (hybrid)
August 23 Wed 14:30-15:30 ALMA-J seminar Zoom
詳細は下記からご覧ください。
=============== August 21 Mon===============
Campus: Mitaka
Seminar: ALMA-J seminar
Regularly Scheduled/Sporadic: Sporadic
Date and time: August 21, 2023 (Mon), 14:30-15:30
Place: ALMA building #102 / Zoom (hybrid)
Speaker: Martin Bureau
Affiliation: University of Oxford
Title: WISDOM: Molecular cloud properties and star-formation quenching
Abstract: Molecular gas is the fuel for star formation in galaxies. Using observations from the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), that spatially resolve (1-30 pc) individual molecular clouds across the Hubble sequence, I will reveal a clear dependence of the nature of the molecular interstellar medium of galaxies on Hubble type, and present a simple diagnostic of cloud formation. In particular, I will highlight the shortcomings of the usual virial approach to clouds as self-gravitating objects, and stress the importance of the external galactic potential and in-plane shear to regulate the dynamical states of clouds. I also introduce a simple but powerful cloud-cloud collision formalism that accounts for the cloud properties of several nearby as well as high-redshift systems. Finally, I note the peculiar properties of clouds within the bars of spiral galaxies, and I discuss the impact of these different mechanisms on the star formation efficiency of clouds and thus the quenching of star formation, particularly in galaxy nuclei and spheroids (morphological quenching).
Facilitator: Bunyo Hatsukade, Kouichiro Nakanishi
=============== August 23 Wed===============
Campus: Mitaka
Seminar: ALMA-J seminar
Regularly Scheduled/Sporadic: Every Wednesday
Date and time: August 23, 2023 (Wed), 14:30-15:30
Place: Zoom
Speaker: Takashi Shimonishi
Affiliation: Niigata University
Title: The Role of Metallicity in the Chemical Evolution of Star-forming Regions
Abstract:
Understanding the chemistry of the interstellar medium at low metallicity is crucial to unveil physical and chemical processes in the past Galactic environment or those in high-redshift galaxies, where the metallicity was significantly lower compared to the present-day solar neighborhood. In the last decade, there has been a great progress in astrochemical studies of interstellar molecules in low-metallicity star-forming regions. Nearby low-metallicity laboratories, such as the Large and Small Magellanic Clouds, Local Group dwarf galaxies, and the outskirts of our Galaxy, play an important role in such studies. Single-dish radio observations have detected various dense gas tracers in those regions, which revealed the molecular-cloud-scale (<1-10 pc) chemistry at low metallicity. With ALMA, emission from dense and high-temperature molecular gas associated with embedded protostars (i.e., hot molecular cores) are detected in the LMC, SMC, and outer Galaxy, which revealed the chemical complexity of star-forming cores (<0.1 pc) at low metallicity. Besides gas-phase species, infrared observations have revealed chemical compositions of ices around deeply embedded protostars in the LMC and SMC. Do molecular abundances simply scale with the metallicity? If not, which processes govern the chemistry in the low-metallicity interstellar medium? In this presentation, I will discuss the role of metallicity in the chemical evolution of star-forming regions based on recent observations of interstellar molecules in low-metallicity environments.
Facilitator: Bunyo Hatsukade, Kouichiro Nakanishi
2023.8.14-2023.8.20
August 15 Tue 15:00-16:00 Tea Talk Zoom / 中央棟北ロビー (hybrid)
詳細は下記からご覧ください。
=============== August 15 Tue===============
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：8/15（火）15：00～16：00
場所：Zoom / 中央棟北ロビー (hybrid)
講演者：Vanessa Moss
Title：Lessons learned from the future of meetings for a better today Looking to the future
Abstract：
Lessons learned from the future of meetings for a better today Looking to the future can tell us a lot about the limitations of today. “The Future of Meetings” (TFOM) began as a symposium dedicated to exploring the future of interaction in 2020, framed around key themes of accessibility, inclusivity, sustainability and technology and with its roots in the astronomy community. Throughout our work in TFOM, it has been clear that the standard meeting practices taken for granted as a given in astronomy (and science) have long been inaccessible to many, creating a “normal” that is both exclusive and unsustainable. Conversely, the rapid advances in effective online means of communicating and collaborating open up a wealth of new possibilities for redefining what is required to succeed in astronomy, from the ground up. In this talk, I will outline the lessons learned from and core recommendations of TFOM, based on our ongoing work as an active community of practice. In the wake of pandemic disruption, we have a unique chance to rewrite the fabric of collaboration within our field and beyond, in order to design a better normal for today, tomorrow and the future. By doing so, we can set a leading example for science, academia and society as a whole, maximising inclusivity while minimising environmental harm at a critical turning point for our long term survival as a species.
Bio：
Dr Vanessa Moss is a radio astronomer based at CSIRO Space & Astronomy in Australia. In her position at CSIRO, she is Head of Science Operations for the groundbreaking ASKAP telescope in remote Western Australia, managing astronomical observations from specification to the arrival of the data at the Pawsey Supercomputing Centre. In her research, she has studied cosmic phenomena across the universe, from the hidden structure of the Milky Way halo to dense gas casting shadows against distant black holes, and is a core member of FLASH (First Large Absorption Survey in HI).
世話人の連絡先：
-名前： Blumenthal Kelly
2023.8.7-2023.8.13
August 8 Tue 10:00-11:00 SOKENDAI Doctoral Thesis Preliminary Evaluation Zoom / Lecture Room (hybrid)
August 9 Wed 15:30-16:30 NAOJ Science Colloquium
Zoom / Large Seminar Room (hybrid)
詳細は下記からご覧ください。
=============== August 8 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：August 8, 2023, 10:00～11:00
Place：Lecture Room and Zoom
Speaker：Nao Fukagawa
Title：Chemical Evolution of Dwarf Galaxies
Facilitator
-Name：Hideyuki Kobayashi
:Natsuko Fujii (Graduate Student Affairs Unit)
=============== August 9 Wed===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2023 Aug. 9, 15:30-16:30
Place：Zoom / the large seminar room (hybrid)
Speaker：Lars Bonne
Affiliation：SOFIA Science Center, USRA, NASA Ames
Title：The assembly and dispersal of dense gas in star forming regions
Abstract：
First, I will present work analyzing multiple spectral lines toward
low- and high-mass star forming regions. The study employs archival HI
data, CO observations from the NANTEN2, APEX, and IRAM 30m
observatories, and [CII] observations with the SOFIA telescope. In these
regions we demonstrated the presence of recurring organized velocity
fields, also found by other authors, which suggests that star formation
is initiated by the same mechanism. Namely, magnetic field bending in
high-velocity (>7 km/s) colliding flows. This appears to be consistent
with magnetic field observations in several nearby clouds, which
suggests that the proposed scenario might be widespread and explain both
low- and high-mass star formation.
In the second part, I will present observations of the [CII] spectral
line by the FEEDBACK legacy program toward ~10 ionized (HII) regions
surrounding massive O stars. [CII] is the main coolant of the neutral
ISM in photodissociation regions (PDRs) and thus an excellent probe to
study the effect of stellar feedback on the host molecular cloud. The
[CII] emission reveals previously undetected high-velocity gas (10-20
km/s) in all regions. This high-velocity gas is the result of expanding
bubbles and continuous mass ejection in flattened molecular clouds. The
detection of this high-velocity gas has reignited the discussion whether
radiation or stellar winds drive molecular dispersal. Quantifying the
mass ejection rates also allows us to make a direct estimate of
molecular cloud dispersal timescales which consistently points to a few
(< 5) Myr. This provides direct observational evidence that molecular
cloud are transient structures and not in quasi-static equilibrium.
Facilitator
-Name：Doris Arzoumanian
-Comment：English