Shun Yin Cheung

Shun Yin Cheung

I am a final-year PhD student studying gravitational waves

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A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

Pages

Posts

Introduction to normalising flows

11 minute read

Published:

In the field of Gravitational-Wave astronomy, I see a transition from traditional stochastic sampling methods such as Monte Carlo Markov Chains and nested sampling towards something called normalising flows. As our inference problems become harder due to the increasing volume of data, we need faster inference methods. In this blog post, we will go through what is a normalising flow and can it solve inference problem that are intractably long for traditional methods.

Introduction to Gaussian processes

16 minute read

Published:

I have used Gaussian process and it being used extensively in fields such as astrophysics. They are very useful and flexible models that can be applied to timeseries data. However, I often find it difficult to explain a Gaussian process (GP) to a non-expert in a short amount of time. While it is easy to use many of the GP libaries available, wrapping your head around the theoretical concepts can be challenging.

Exploring factors and causes in student stress using a clustering algorithm

4 minute read

Published:

Recently, I came across this kaggle dataset for student stress suvery conducted nationwide. There are 20 factors where participants must give a numerical score to rate how prevalent these factors are. This dataset is pretty interesting as stress is something that affects us all, and understanding what factors are correlated with increased stress levels can improve our quality of life.

portfolio

publications

Does spacetime have memories? Searching for gravitational-wave memory in the third LIGO-Virgo-KAGRA gravitational-wave transient catalogue

Published in Classical and Quantum Gravity, 2024

Gravitational-wave memory is a non-linear effect predicted by general relativity that remains undetected. We apply a Bayesian analysis framework to search for gravitational-wave memory using binary black hole mergers in LIGO-Virgo-KAGRA`ShunYCheung.github.io/_publications/memory_paper.mds third gravitational-wave transient catalogue.

Recommended citation: Shun Yin Cheung et al 2024 Class. Quantum Grav. 41 115010
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A search for extra polarisations using a Gaussian process in Gravitational-Wave Transient Catalogue 3

Published in The Astrophysical Journal (submitted), 2025

General relativity predicts that gravitational waves are described by two polarisation states: the plus state and cross state. However, alternate theories of gravity allow up to six polarisations. We employ the gravitational-wave null stream, a linear combination of three or more detectors where the and signals add to zero, leaving behind noise and potentially gravitational waves in non-standard polarisation states. We develop a Gaussian process model to search for extra polarisations beyond general relativity. Using data from 42 three-detector events from LIGO-Virgo-KAGRAs Third Gravitational-Wave Transient Catalogue, we find no evidence of non-standard polarisations. We set upper limits on the fractional deviation in gravitational-wave strain to be as low as 0.39 at 90% credibility for the event GW190602_175927.

Recommended citation: TBD
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talks

teaching

Teaching experience 1

Undergraduate course, University 1, Department, 2014

This is a description of a teaching experience. You can use markdown like any other post.

Teaching experience 2

Workshop, University 1, Department, 2015

This is a description of a teaching experience. You can use markdown like any other post.