27. 10. 2020 Issue 70
Discovering the Biggest Gravitational Wave Source So Far

Recently, the Laser Interferometer Gravitational-wave Observatory (LIGO) Scientific Collaboration and the Virgo Collaboration (Virgo) reported the discovery of GW190521, the first ever detected intermediate-mass black hole which reaches a mass larger than was thought possible. Professor Tjonnie Li and Professor Juan Calderon Bustillo of Department of Physics lead the only group in Hong Kong involved with the work of LIGO, and have been deeply involved in the analysis of the signal.

To date, we have known about two different populations of black holes. Stellar black holes with masses less than about 100 times that of the Sun and supermassive black holes with up to billions of times the mass of the Sun. GW190521 was detected on 21 May, 2019 by three interferometers and the detailed analysis of the signal indicates that the creature with 142 solar masses was produced by the fusion of two black holes of approximately 85 and 66 times the mass of the Sun, which is the first evidence of a black hole in this mass range. The ground-breaking discovery helps scientists to understand how stars live and die and suggests them to revisit the current models of black hole formation.
Further reading:
Abbott, R., Abbott, T. D., Abraham, S., Acernese, F., Ackley, K., Adams, C., ... & Agatsuma, K. (2020). GW190521: A Binary Black Hole Merger with a Total Mass of 150 M⊙. Physical Review Letters, 125(10), 101102. DOI: https://doi.org/10.1103/PhysRevLett.125.101102
Abbott, R., Abbott, T. D., Abraham, S., Acernese, F., Ackley, K., Adams, C., ... & Agatsuma, K. (2020). Properties and astrophysical implications of the 150 M⊙ binary black hole merger GW190521. The Astrophysical Journal Letters, 900(1), L13. DOI: https://doi.org/10.3847/2041-8213/aba493

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Table of Contents
Professor CHOW Hei Man Kim – Big Data X Traditional Molecular Biology: Decoding Biological Signalling Network
Welcoming New Students
ZOOM Consultation by Science Student Academic Advisors
Mini Impact Symposium – From Research to Entrepreneurship
Virtual Information Day for Undergraduate Admissions 2020
Revealing Gravitational-Wave Signature of a First-Order Quantum Chromodynamics Phase
Finding Slow Earthquakes Behave Similarly to Regular Earthquakes
Discovering the Biggest Gravitational Wave Source So Far
Striving to Find Interdisciplinary Answers to Environmental Problems
Young Scientists Receiving Excellent Young Science Fund 2020
The XPLORER PRIZE (Mathematics and Physics)
Probing Deep into Shallow Earthquakes Induced by Shale Gas Production in Sichuan
Breaking the Wall of Cryosphere Monitoring
MoE Higher Education Outstanding Scientific Research Output Award
Trials and Triumphs with Biochemical Research

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