SHAO Astrophysics Colloquium
Title: Probe of Supernova Progenitors with Gamma-rays
Speaker: Wei Wang (Wuhan University)
Time: 3 pm, September 27 (Thursday)
Location: Lecture Hall, 3rd floor
Abstract: Supernovae (SNe) have the subclasses of core-collapse supernovae (Type II, Type Ib/Ic) and thermonuclear explosions (Type Ia). However, the central explosion mechanisms for the different types of SNe are not well understood. The radioactivity isotopes, i.e., 44Ti and 56Ni, are produced in the central explosion region of SNe. Detection of the gamma-rays emitted by these isotopes can constrain the mechanism of supernova explosions and the supernova progenitors. I will introduce the recent results of gamma-ray observations: constraining explosion mechanism of core-collapse SNe by detecting 44Ti in CAS A and SN 1987A; progenitors of Type Ia SNe probed by 44Ti in Tycho and 56Ni in SN 2014J. In addition, the diffuse 60Fe gamma-ray emission in the Galaxy can constrain the nuclear reactions and nucleosynthesis models in SNe. Future possible development of gamma-ray detectors is also discussed.
Brief CV
Wei Wang, the professor of School of Physics and Technology, Wuhan University, obtained the BSc degree in Department of Astronomy, Nanjing University in 2000, a MSc degree in National Astronomical Observatories, CAS in 2003, and the Ph.D. degree in Max-Plank Institute for Extraterrestrial Physics, Germany in 2007. His main research interest concentrates on neutron stars, pulsars, magnetars, X-ray binaries, supernovae, supernova remnants, gamma-ray astronomy, nuclear astrophysics. He has published more than 60 refereed papers. He got the support by the Outstanding Youth Fundation of National Natural Science Fundation in 2016.
Seminar talk
Title: Imaging Event Horizons---a Journey Walked Together by Observers and Theorists
Speaker: Chi-Kwan Chan (Univ of Arizona)
Time: 10 am, September 25 (Tuesday)
Location: Lecture Hall, 3rd floor
Abstract: Black holes, unlike many astronomical objects, were first predicted theoretically as a direct consequence of Einstein's General Theory of Relativity. They were initially thought unphysical, even by Einstein himself. Although we have many indirect evidences that support their existences after decades of discoveries and observations, to date, there is no direct observation of black holes. This will soon change. The Event Horizon Telescope (EHT), a Very-Long-Baseline Interferometry (VLBI) experiment that links together multiple radio telescopes around the globe, had a very successful observing campaign in 2017. Since then, it has made significant progresses in processing and analyzing the data. As a theorist working in this large scale observation project, I will report my perspectives in this talk.
Bio: Chi-kwan Chan works with cutting edge technologies to advance scientific research. An avid coder and an expert in computational astrophysics and high performance computing, Chi-kwan has developed new algorithms to solve complex physical systems, used graphics processing units (GPUs) to accelerate numerical simulations, designed cloud computing infrastructures to handle large data sets, and applied machine learning algorithms to speed up and automate data processing. Some of Chi-kwan's active projects include capturing images of black holes (the Event Horizon Telescope project) and visualizing numerical simulations in virtual reality.
Chi-kwan is currently an astronomer at the Steward Observatory and a Data Science Fellow at the Data Science Institute at the University of Arizona. He is also a coordinator of the Software and Data Compatibility Working Group of the EHT.
Group meetings
Black hole Accretion and High-energy Astrophysics /Black Hole Feedback and Cosmic Ray Astrophysics Seminar
Location: 1608
Time: 14:00-16:00, Wednesday, September 26th
Speaker: Defu Bu
Global Evolution of an Accretion Disk with a Net Vertical Field: Coronal Accretion, Flux
Transport, and Disk Winds
http://adsabs.harvard.edu/abs/2018ApJ...857...34Z
Speaker: Peiyao Xu
Magnetic Flux Paradigm for Radio Loudness of Active Galactic Nuclei
http://adsabs.harvard.edu/abs/2013ApJ...764L..24S
