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Quantitative morphology of galaxy clusters at X-ray wavelengths

Hunt, Laura


Laura Hunt


Kevin A. Pimbblet

Brad K. Gibson


We apply quantitative morphology techniques to X-ray imaging of clusters of galaxies to determine correlation between calculated parameters (CAS, Gini and M20) and features such as bow shocks, cold fronts, gas sloshing, Kelvin-Helmholtz instabilities (KHI), X-ray cavities and relaxed/disturbed clusters. In order to do this we create a novel sample of 51 cluster images from archival data such as πΆβ„Žπ‘Žπ‘›π‘‘π‘Ÿπ‘Ž and 𝑋𝑀𝑀 βˆ’ π‘π‘’π‘€π‘‘π‘œπ‘› based on selection criteria spanning a redshift 0.01 < 𝑧 < 0.07 and X-ray luminosity 𝐿π‘₯ > 1 Γ— 1044 ergs sβˆ’1. We process the original images, and remove foreground sources and CCD gaps, and apply adaptive kernel smoothing on the central 3 Mpc of the clusters which is determined using an asymmetry technique to weight the luminosity centroid of the image. For each image we calculate the concentration of light C, the asymmetry index A, the clumpiness parameter S, the Gini coefficient G and the M20 parameter. We attempt to correlate these results with the physical features present and demonstrate that the presence of bow shocks is correlated with higher M20 and lower C and S, cavities correlate with low G and S, cold fronts show low S and G and higher M20, low S and high M20 correlate with gas sloshing and clusters that exhibit KHI have high S values.


Hunt, L. (2021). Quantitative morphology of galaxy clusters at X-ray wavelengths. (Thesis). University of Hull. Retrieved from

Thesis Type Thesis
Deposit Date Aug 2, 2022
Publicly Available Date Feb 24, 2023
Keywords Physics
Public URL
Additional Information Department of Physics and Mathematics, The University of Hull
Award Date Sep 1, 2021


Thesis (3.6 Mb)

Copyright Statement
Β© 2021 Hunt, Laura. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.

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