The first detection of gravitational waves from a binary neutron star merger GW170817 by the LIGO-Virgo Collaboration has provided fundamental new insights into the astrophysical site for the r-process nucleosynthesis and on the nature of dense neutron-star matter. The detected gravitational wave signal depends upon the tidal distortion of the neutron stars as they approach merger. We examine how the detected “chirp” depends on the adopted equation of state. This places new constraints on the properties of nuclear matter. The detected evidence of heavy-element nucleosynthesis also provides insight into the nature of the r-process and the fission properties of the heaviest nuclei. Parametrically, one can divide models for the r-process into three scenarios roughly characterized by the number of neutron captures per seed nucleus (n/s). In addition to neutron-star mergers, these include magneto-hydrodynamic jets from supernovae and the neutrino heated wind above the proto-neutron star in core-collapse supernovae. Insight from GW170817 allows one to better quantify the relative contributions of each astrophysical site.
Solar eruptive phenomena occur at different spatial, temporal and energy scales. A flare is the most violent form of solar activity which essentially represents sudden release of excess energy stored in the magnetic fields of solar corona. The contemporary multi-wavelength observations have immensely improved our understanding of the various physical processes occurring in different atmospheric layers of the Sun during a solar flare. The standard flare model has been successful in broadly recognizing these physical processes as the consequence of large-scale magnetic reconnection in the corona. Jets and coronal mass ejections are among important phenomena associated with solar flares.
The objective of the present talk is to summarize the multi-wavelength observations of solar flares and associated phenomena taken mainly from the space borne instruments over the last decade. I will highlight some recent works on magnetic field modelling of the active region corona that shed light upon the triggering and energy release mechanisms. I will also briefly discuss contemporary observations on flare-flux rope-CME associations in the lower corona and their space weather consequences.
At the Royal Society in London on July 20, 2015, Yuri Milner, Stephen Hawking and Lord Martin Rees announced a set of initiatives — a scientific programme aimed at finding evidence of technological life beyond Earth entitled 'Breakthrough Listen’, and a contest to devise potential messages named 'Breakthrough Message’. In addition, atop the One World Trade Center in New York on April 20, 2016, Breakthrough Starshot was announced, an interstellar programme to Alpha Centauri. These are the first of several privately-funded global initiatives to answer the fundamental science questions surrounding the origin, extent and nature of life in the universe. The Breakthrough Initiatives are managed by the Breakthrough Prize Foundation.
I have attempted to utilize network science tools for investigating topological structures of the Universe. In this talk, I provide an overview of network science and present the results of my three pilot studies applied to the data from COSMOS, Illustris, and NDWFS. Then, I briefly demonstrate and discuss about how we can apply the modern Big Data platform, Apache Spark, to astronomical data-driven problems.
It has now been proven that the Universe is mostly filled with what we cannot see; dark energy and dark matter. The presence of dark matter had profound consequences on the evolution of the Universe. The Standard Model does not accommodate a suitable dark matter candidate. Therefore the existence of dark matter is a crucial phenomenological evidence for physics Beyond the Standard Model. The pressing goal of current and future dark matter experiments is to answer the question of whether dark matter interacts with normal matter other than gravity; i.e. if dark matter is detectable. Among the plethora of dark matter candidate particles, the Weakly Interacting Massive Particles (WIMPs) and the Axions are the most outstanding contender. In this talk, I will discuss about the dark matter axion search projects at KAIST/IBS.
Thanks to modern technology - wide-field camera, high computing power, massive data storage, and robotic observation - it is possible to obtain thousands of asteroid light curves within a short period of time. Therefore, several important applications can be conducted on asteroids in a more comprehensive way. For instance, the interior structure can be studied through the spin-barrier, the mechanisms changing asteroid spin status can be learned through the spin-rate distribution, and the discoveries of binary asteroid, etc. Moreover, the super-fast rotating asteroids, a kind of odd objects against the current rubble-pile structure, can refresh our understanding of asteroid. I will talk about our asteroid time-series survey using wide-field facility, such as the PTF/ZTF, the PS1, the Xuyi observatory and the KMTNet, and what we have learned so far.
AWS에서 바라보는 AI & Deep Learning 관련 서비스들에 대한 소개와 함께, AWS에서 제공되는 public data sets에 대해서도 설명을 하고자 합니다. 더불어서 (천문 우주) 과학 분야 연구에서 AWS 활용에 대해서도 의견을 전하고자 합니다.
Over the last three decades, our knowledge about planetary systems has increased dramatically, from one example with eight planets (our own Solar system) to over 2600 planetary systems hosting more than 3500 planets. While occurrence rate studies show that exoplanets are the rule rather than an exception our understating of how these planets form, in different environments and around different stars, is still limited. However, we are now on the verge of the next revolution in exoplanet science. TESS, PLATO, JWST, WFIRST, and LSST will complete the demographic census of planets across a wide range of environments, and will allow detailed characterization of their atmospheres and structure.
In this talk I will discuss the important role of microlensing in the forefront of exoplanetary studies. Gravitational microlensing is unique in its ability to probe several relatively untapped reservoirs of exoplanet parameter space, including planets near the "snowline," planets throughout the Galaxy, and the population of free-floating planets. A wealth of new and upcoming microlensing campaigns, both from ground and space, will allow the full exploration of the exoplanet demographics unique to microlensing. Specifically, I will present the key results from the first space microlensing campaigns, with Spitzer, which enable the first estimate of the Galactic distribution of planets, and preliminary results from the first NIR microlensing survey, with UKIRT, mapping the microlensing event rate and event timescale distribution near the Galactic center, which are inaccessible to optical surveys due to the high extinction. These are crucial for the microlensing survey planned with NASA flagship mission WFIRST, which is scheduled to launch in mid-2020, and will discover thousands of snowline exoplanets via their microlensing light curves, enabling a Kepler-like statistical analysis of planets at 1-10 AU from their parent stars and potentially revolutionizing our understanding of planet formation.
The MESSIER satellite has been designed to explore the extremely low surface brightness universe at UV and optical wavelengths. The two driving science cases target the mildly- and highly non-linear regimes of structure formation to test two key predictions of the LCDM scenario: (1) the detection of the putative large number of galaxy satellites, and (2) the identification of the filaments of the cosmic web. The science requirements imply challenging instrumentation issues which have only recently been solved. The satellite will drift scan the entire sky in 6 bands covering the 200-1000 nm wavelength range to reach the unprecedented surface brightness levels of 34 mag/arcsec^2 in the optical and 37 mag/arcsec^2 in the UV. As usual when uncovering new volumes in parameter space, many important secondary science cases will also result as free by-products and will be discussed in some detail: the actual luminosity function of galaxies, the contribution and role of intracluster light, the fluctuations of the cosmological background radiation at UV and optical wavelengths, the warm molecular hydrogen content of galaxies at z=0.25, time-domain studies of supernovae and tidal disruption events, the chemical enrichment of the interstellar medium through mass loss of red giant stars and the accurate measure of the BAO scale at z=0.7 with over 30 million galaxies detected in Lyman-alpha at this redshift. It will provide the first space-based reference UV-optical photometric catalogue of the entire sky. Synergies with GAIA, EUCLID and WFIRST will also be discussed, along with some of the statistical challenges involved in the data analysis.
Hayabusa2 is the second sample return mission from an asteroid after Hayabusa mission. The target asteroid is (162173) Ryugu, which is a C-type asteroid. The main science objective is to investigate organic matters and water at the beginning of the solar system. The technological purpose is to maturate the new technology developed by Hayabusa and to develop other new technology for space missions.
Hayabusa2 was launched December 3, 2014 by an H-IIA launch vehicle from Tanegashima Space Center in Japan. Just one year later, on December 3, 2015, Hayabusa2 came back to the Earth to execute the Earth gravity assist, which was successfully done and its orbit was changed toward Ryugu. We observed the Earth and the moon by using the remote sensing instruments on board at the Earth gravity assist. Then after three long-term ion engine operations, Hayabusa2 will arrive at Ryugu in June or July of 2018. At first, we will observe Ryugu carefully and decide the landing place. Then we will release the lander and rovers, execute touchdown once or twice, and try the experiment of the impactor. Hayabusa2 will leave Ryugu at the end of 2019 and bring back the capsule to the Earth at the end of 2020.
At present, we are just before arriving at Ryugu. In order to prepare for the operations near the asteroid, we have done two kinds of trainings, that is, Landing Site Selection (LSS) training and Real-Time Integrated Operation (RIO) training. We hope we can explore Ryugu smoothly and we are sure that we can study a lot of new things from Ryugu.
Catastrophic collisions have shaped the destiny of the Solar System, and perhaps even humankind. In 1994, a series of massive explosions occurred on Jupiter after the remnants of a fractured comet plunged into that planet's atmosphere. Dr. Hammel led the Hubble Space Telescope team that tracked these explosions. When a fresh Jupiter impact site was discovered just 15 years later, Dr. Hammel and her colleagues used Hubble and the Gemini Observatory to determine that this was the result of an errant asteroid. Dr. Hammel will explain what happened on Jupiter during these cosmic collisions. More importantly, she will explain the implications of such cosmic collisions for us here on Earth. She will conclude with how AURA’s facilities (Hubble, Gemini, the Blanco telecope’s DECam, and the soon-to-be-completed LSST) will help us predict and prevent catastrophic impacts on Earth.
NASA is discussing "what they want to know next 30 years [science]” and “what it takes to make that happens [technology]” in order to answer the fundamental questions “Are we alone?” and “What is the origin and history of our solar system and extrasolar systems?” under the frame of (i) Discovery and (ii) Exploration of other worlds and cosmos and (iii) Development of necessary technologies. Searching for life and habitable environments outside Earth will be a driving force for many NASA projects. Next 30 years will be the decades of “sample returns” from asteroids and Mars. With the accumulation of scientific knowledge and technology through various missions including the exploration to Mars, NASA is paving a way for human exploration and noticeably shifting its focus to the water world Europa. When James Webb Telescope is put into the orbit in year 2018, it will detect and analyze water, oxygen, methane, ozone, temperature, surface pressure and many more on planets, especially seven exoplanets of TRAPPIST 1 solar system. The close comparative study of exoplanets and water and icy worlds in our solar system is expected as an effort to understand “life and its origin”. NASA will continue to examine the possibility to transform Mars into a habitable environment. This talk is intended to show the big picture under the overarching themes of NASA missions so that audience have a good foundation from which they can nurture their abilities to forecast what NASA and thus the international space exploration community try to achieve and where they will be next 10 years, 20 years, and 30 years.