Unraveling the Many Facets of Supernova Remnants in High-energy and Their Link to Galactic Cosmic Rays

Thursday 10 Oct 2013, 15:00 → 16:00 Asia/Tokyo

Main Research Bldg. 2F Rom 224 (RIKEN Wako)

============================================================ 第137回 「高エネルギー宇宙物理研究室 知の共有ゼミ」 のご案内 ============================================================ 日時 : 2013年10月10日 (木曜日) 15:00から 会場 : 研究本館224号室 (room 224 in the main building) 講師 : Shiu-Hang (Herman) Lee (RIKEN Astrophysical Big Bang Laboratory) 題目 : Unraveling the Many Facets of Supernova Remnants in High-energy and Their Link to Galactic Cosmic Rays 概要 : We can be easily deceived by a serene, tranquil night sky that our Universe is a quiet and more-or-less changeless place. In fact, every now and then, gigantic explosive phenomena are occurring here and there in outer space that can generate an almost inconceivable amount of energy. Even within our own Milky Way galaxy, some stars can end their life as 'supernovae', massive explosions 10 trillion times more energetic than nuclear bombs that drive stellar material into the interstellar space at supersonic speeds. These explosions create powerful shockwaves that heats up the interstellar gas and ejected stellar material to millions of degree, giving rise to the magnificent looks of these exploded stars in X-ray for hundreds and thousands of year after the supernovae. At these shocks, charged particles such as protons and electrons are also boosted to energies that can be substantially higher than what man-made particle accelerators can achieve (i.e. cosmic accelerators!). The debris of these dead stars, or supernova remnants (SNRs), are treasure troves of large-scale high-energy phenomena that can never be studied directly in laboratories. In this talk, I will first give a short overview of what we have learnt so far about SNRs, including the many outstanding questions and mysteries, from lots of ground-based and space telescope observations. Then I will introduce our recent numerical studies of young shell-type SNRs using a cutting-edge simulation code we have been developing, with focus on their multi-wavelength emission from radio to TeV gamma-rays. I will discuss how our numerical models can offer vital clues to the poorly understood particle acceleration mechanism at SNRs, and hence the long-postulated link between SNRs and the origin of cosmic rays in our Galaxy. If time allows, I will also touch on the recent measurements of cosmic rays by the PAMELA and AMS-02 spacecrafts, and comment on a possible astrophysical explanation of the so-called 'anomalous positron excess' feature discovered in these new data. 知の共有ゼミ