2月9日（火）13：30～15：00 太陽系小天体セミナー zoom
Feb 9 Tue Solar System Minor Body Seminar
2月10日（水）13：30～15：00 NAOJ Science Colloquium zoom
Feb 10 Wed
2月10日（水）15：00～16：00 ALMA-J seminar zoom
Feb 10 Wed
2月12日（金）13：30～15：00 Solar and Space Plasma Seminar zoom
Feb 12 Fri
詳細は以下をご覧下さい。
2月9日（火）
- 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
- 2月9日（火曜日）13時30分～15時
- 場所
- zoom
- 講演者
- 石村周平
- 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
2月10日（水）
- Campus
- Mitaka
- Seminar
- NAOJ Science Colloquium
- Regularly Scheduled/Sporadic
- Every Wednesday
- Date
- 2021 February 10
- Time
- 13:30-15:00
- Place
- Zoom
- Speaker
- Miroslav Filipovic (Western Sydney Univ.)
- Title
- Supernova Remnants in Magellanic Clouds: Multifrequency approach
- Abstract
-
This is an exciting time for the discovery of supernova remnants (SNRs) in our and other nearby galaxies. SNRs reflect a major process in the elemental enrichment of the interstellar medium (ISM). The study of this interaction in different domains including gamma-ray, radio, optical, IR and X-ray, allow a better understanding of these objects and their environments. Nearby galaxies offer an ideal laboratory, since they are near enough to be resolved, yet located at relatively known distances.
We are currently carrying out observational studies of SNRs and superbubbles using today’s gamma-ray (HESS), X-ray (Chandra, XMM) and radio telescopes (ATCA, MWA) and will continue our efforts with upcoming telescopes like eROSITA, Cherenkov Telescope Array, and the SKA precursors, including synergistic programmes such as ASKAP-eROSITA-MeerKAT. SKA pathfinders’ observations in radio at low frequencies with high sensitivity will detect new SNRs in our Galaxy and the MCs, which are either old and too faint, young and too small, or located in a too confusing environment and have thus not been detected yet. In addition, the SKA pathfinders’ observations will also allow high-resolution polarimetry and are key to the study of the energetics of accelerated particles as well as the magnetic field strength and configurations. Gamma-ray studies provide answers to the long-standing question in high energy astrophysics: Where do cosmic rays come from? The gamma-ray emission seen from some middle-aged supernova remnants (SNRs) is now known to be from distant populations of cosmic-rays (probably accelerated locally) interacting with gas, but there is still much work to be done in accounting for the Galactic cosmic-ray flux. Young PeV gamma-ray supernova remnants require different techniques to address the question of cosmic-ray acceleration. The Cherenkov Telescope Array will allow us to do this.
I will present an overview of our ongoing and very recent multi-wavelength studies of the young (and some not-so-young) SNRs in the Magellanic Clouds and our Galaxies. Finally, I will present our strategies for the next 10 years on how to observe SNRs with the next generation of instruments — from ASKAP/MWA2 via eROSITA to CTA and whoever else. - Facilitator
- -Name：Akimasa Kataoka
2月10日(水）
- Campus
- Mitaka
- Seminar
- ALMA-J seminar
- Regularly Scheduled/Sporadic
- Every Wednesday
- Date and time
- 2021 Feb. 10 15:00-16:00
- Place
- Zoom
- Speaker
- Tomonari Michiyama (Kavli Institute for Astronomy and Astrophysics)
- Title
- A Survey of [CI], CO(4-3), and Dust Continuum in Nearby U/LIRGs — Band 8 and Morita Array Observations
- Abstract
-
In this seminar, I explain the survey results of [C I], CO(4-3), and Dust continuum for
36 nearby Ultra/Luminous Infrared Galaxies (U/LIRGs) using the Band 8 receiver mounted on Atacama Compact Array (ACA, Morita Array) of Atacama Large Millimeter/submillimeter Array. The main analysis and results are as follows. (i) We discovered the candidates of [CI]-poor galaxies. For example, in NGC 6052 and NGC 7679, CO(4-3) is detected but [C I], is not detected with the [C I]/CO(4-3) ratio of 0.08. (ii) We investigate the consistency between molecular gas mass (MH2) measured by Band 8 information and MH2 derived by CO(1-0) and dust mass. Our analyses suggest that [C I] is not significantly superior to CO (4-3) and dust continuum as a substitute of CO (1-0) when we measure molecular gas mass. (iii) We compare our nearby U/LIRGs with high-z galaxies such as galaxies on star formation main sequence (MS) at z~1 and submillimeter galaxies (SMGs) at z = 2 -4. We find that the mean value of [C I]/CO(4-3) ratio of U/LIRGs is similar to SMGs but smaller than galaxies on MS. This suggests a higher hydrogen density in U/LIRGs and SMGs than galaxies on MS assuming a simple photodissociation model. - Facilitator
- Hiroshi Nagai, Xing Lu
2月12日(金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 12 February (Fri), 13:30-15:00
- Place
- zoom
- Speaker
- Joten Okamoto
- Affiliation
- ALMA/NAOJ
- Title
- Investigation of the temporal variation of magnetic field strength in the solar chromosphere with CLASP2
- Abstract
-
Magnetic field in the chromosphere is one the most important parameters to understand the dynamics of the solar atmosphere and to solve the coronal heating problem. To verify a new technique to observe the chromospheric magnetic field, we developed a new instrument, CLASP2 (Chromospheric LAyer SpectroPolarimeter), which measures the full Stokes profiles across the Mg II k and h lines around 280 nm. The launch operation was performed on 2019 April 11 at the White Sands Missile Range, USA, and we successfully acquired data during a six-minute exo-atmospheric flight. From the initial result using time-integrated Stokes I and V data taken at the plage over two and a half minutes, we confirmed that the line-of-sight magnetic field at multiple altitudes of the chromosphere can be measured.
Next, the temporal variation of the magnetic field strength was investigated for further application to scientific research, especially with the influence of waves on the magnetic structure. We verified the effect of different integration in time and space on the fitting results of the spectral data, and examined the integration time in the CLASP2 re-flight plan (CLASP2.1), which will perform a slit-scan observation.
I will show the results and conclude that the field strength inferred from the core of the Mg lines can be measured in an average error of 30 Gauss with an integration time of 15 sec, but that the temporal variation is not reliable. - Facilitator
- -Name：Munehito Shoda