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2020-10-08 Abstract

Title: The extremes of the transient Universe: entering the golden age of time-domain astrophysics
 
Speaker:  Dr. Ting-Wan Chen (Stockholm University)
 
Date: December 08 at 16:00
 
Location: R521, General Building II
 
Abstract: 

In the last ten years, the new generation of wide-field, time-domain sky surveys have revolutionised astronomy. Among the most exciting new discoveries are 'superluminous supernovae’, 10-100 times brighter than normal supernovae, which were not predicted by existing theory. Despite being the focus of intense interest, the cause of their extreme luminosity is still not well established. More recently, gravitational waves (GWs) from a binary neutron star merger were detected by LIGO-Virgo, and we discovered the first ever optical counterpart to a GW source, the so-called ‘kilonova’. 
In this talk, I will discuss these two new classes of stellar explosions. First I will show how the host galaxies of superluminous supernovae provide crucial insight into their progenitors, and how the results of detailed monitoring, from my programs with several ESO telescopes, are now converging on a rapidly rotating, highly magnetised neutron star as a consistent explanation for the luminosity. I will then show the results of my GW follow-up program with the Gamma-ray Burst Optical/Near-infrared Detector (GROND), a 7-channel imager perfectly suited to mapping the fast photometric evolution of a kilonova, focusing on the spectacular case of GW170817. The observed light curve of the kilonova is remarkably consistent with the radioactive decay of r-process (neutron-rich) elements, confirming neutron star mergers are an important source of heavy element production. I will finish this talk with a look towards the future, the crucial questions for the Rubin Observatory era, and my strategy for realising the potential of rare and hyper-energetic explosions to transform our understanding of the dynamic sky.

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