Interstellar nanoparticles, including polycyclic aromatic hydrocarbons (PAHs), are believed to play an important role in modern astrophysics. Mid-infrared emission from PAHs is widely used as a tracer of star formation activity. PAHs is also thought to be a leading carrier behind the long-standing mystery of Diffuse Interstellar Bands (DIBs). In this talk, I will discuss new insights into the crucial importance of interstellar nanoparticles. I will start with a review on anomalous microwave emission (AME) by rapidly spinning nanoparticles, which is a critical challenge for early universe study via cosmic microwave background (CMB) radiation. Then, I will present a new way to tracing magnetic fields via polarized mid-IR emission from PAHs. Finally, I will discuss future perspectives to study interstellar nanoparticles through multiwavelength observations with Square Kilometer Array and ALMA Band 1.
The substorm is a dissipation process of the energy stored in the magnetotail, causing active auroras in the nightside polar regions. What processes in the magnetotail trigger the substorm is a major issue in magnetospheric research and has been extensively debated for decades. To understand the substorm triggering mechanism, I statistically studied substorm-associated evolution of the near-Earth magnetotail, using more than ten years of plasma, and magnetic and electric field data mainly from the Geotail spacecraft. I also analyzed data from the recent five THEMIS spacecraft. My results revealed the overall morphological picture of substorm-associated magnetotail evolution as well as energy release and transport and clarified that magnetic reconnection in the near-Earth magnetotail plays an essential role in substorm triggering.
While morphology has been the dominant property to describe and classify galaxies, spin is emerging newly as an alternative and perhaps more fundamental property of a galaxy. Integral field unit spectros revealed that the majority of elliptical galaxies do have a substantial rotational component unlike previous understanding. I present a new result from cosmological-volume hydrodynamic simulations and discuss the origin of spin of galaxies.
The Hyper-Kamiokande (Hyper-K) is a next generation experiment based in Japan succeeding the Super-Kamiokande (Super-K) experiment which achieved the 2015 Nobel prize. It will consists of two identical 260 kton water Cherenkov detectors, 20 times bigger than Super-K, to cover particle physics to astronomy.
The main goals are to solve important problems remaining in neutrino physics using J-PARC neutrino beam, and to detect Super Nova burst/relic neutrinos as well as to search for proton decay and dark matter. Hyper-K is indeed a multi-purpose experiment and telescope from precise measurements to new discoveries.
If one of the detectors is located in Korea instead of the two in Japan, then the physics sensitivities will improve. World-class discoveries are expected and Korea will play a critical role by co-leading the experiment. There are several good candidate sites in Korea to host a Hyper-K detector thanks to higher mountains to reduce spallation background and better quality of rocks to excavate than Japan.
In this talk I will focus on the Hyper-K as a neutrino telescope which will run for 30 years or more.
Initially stimulated by the predictions of high resolution LCDM simulations (e.g. Millennium and Aquarius) and then dramatically advanced by scrutinizing large digital imaging data sets such as SDSS, Pan-STARRS, and the Dark Energy Survey, our picture of the Milky Way and its satellite population has dramatically changed in the past decade. After an overview of our historical understanding of the Milky Way and its dwarf galaxies I will reflect over the tremendous progress in the emerging field of ultra-faint stellar systems, present the most fascinating results we were able to obtain and discuss the new mysteries waiting for us to be solved in future research.
This colloquium is partly supported by the BK21 Plus of Chungnam National University.
2016년 12월 31일 기준으로 인터스텔라의 누적 관객수는 10,304,503명으로 천만 관객 이상 영화로는 역대 15위입니다. 인터스텔라 흥행의 성공 요인은 천체물리학이나 양자역학 등 방대한 과학 주제들을 3시간에 걸쳐 뛰어난 visual effect로 보여 주었다는 것입니다. 영화 인터스텔라의 제작에서 킵손 박사와 영국의 Double Negative라는 시각효과 회사가 협업을 한 것처럼, 국내의 척박한 과학 콘텐츠 현실에서도 어려운 천체물리학을 computer graphics를 이용한 표현을 통해서, 대중에게 소개하는데 새로운 기회를 마련할 수 있을 것으로 예상해 봅니다. 웜홀, 중력렌즈, 빅뱅 등 이해하기 힘든 천체물리학의 주제들을 시각적으로 표현하는 것은 그 자체로도 의미가 있고, 이러한 노력은 학문의 분야에만 제한되지 않고 학계가 대중에게 천체물리학을 소개하는 과정에서 관심을 두어야 하는 부분입니다. 이번 강연에서는 천체물리학을 전공한 연구자가 Double Negative와 협업으로 성공적인 과학 콘테츠를 제작할 수 있었던 것처럼, LG엔시스가 virtual reality 천문우주 과학 콘테츠 제작에 대해서 가지고 있는 계획 등을 소개하도록 하겠습니다. LG엔시스에서는 가상현실 몰입감을 극대화 하고 대중화를 위한 방안으로 4D 모션체어 기반 HMD(Head-Mounted Display), 반구형 돔(Dome)을 제안하고 있습니다. 4D 모션체어 기반 HMD, 반구형 돔이 어떻게 천문우주 과학 콘텐츠 확산하는데 대안이 될 수 있는지 알아보도록 하겠습니다.