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<span style="font-size: 14px;">Reminder of the lunch talks today at 1pm in A113!</span></div>
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<span style="font-size: 14px;">Joe</span></div>
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<div>On 19 May 2025, at 9:00, Joseph Butler <ppxjb4@exmail.nottingham.ac.uk> wrote:</div>
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<div>Hi everyone,
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<div>This week we have two talks that will be given in our lunch talk slot. The first will be given by Jacob, and the second will be given Sara Santoni, a PhD student from Sapienza University of Rome visiting the department this week. As per usual, this will
be at 1pm Thursday in A113, but keep in mind that we’ll be using the full hour. Title and abstracts are below.</div>
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<div class="elementToProof" style=""><b>Jacob Campbell</b>: Dark matter substructure detection using gravitational lensing and machine learning</div>
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<div class="elementToProof" style="">Simulations have shown that dark matter not only forms as a large halo around galaxies, but also as a population of smaller subhaloes. The mass function of these subhaloes is dependent on the dark matter model used, therefore
constraining this mass function can provide valuable insight into the nature of dark matter. Gravitational lensing provides a promising method for both detecting the presence of subhaloes as well as measuring their masses by searching for perturbations in
Einstein rings. The upcoming surveys of Euclid and LSST are expected to provide ~100,000 observations of new lensed systems, therefore it is important to develop a method that allows us to quickly identify and determine the mass of subhaloes. In this talk,
I will explore the prospect of using a machine learning based method for subhalo detection in preparation for these surveys, as well as looking at the limitations and potential issues that we expect to face.</div>
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<div><b>Sara Santoni</b>: <span style="">The Three Hundred project: estimating the dependence of cosmic filaments on galaxy clusters properties from 3D and 2D maps. </span></div>
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<div style="">Galaxy clusters reside in the densest areas of the universe and are intricately connected to larger structures through the filamentary network of the cosmic web. In this framework, matter flows from lower density areas to higher density ones.
As a result, galaxy clusters are deeply influenced by the presence of cosmic filaments attached to them, which can be quantified by a parameter known as connectivity. We benefit from the extensive data set of The Three Hundred hydrodynamical simulation, which
provides 324 simulated cosmological regions, centred on massive galaxy clusters. We extract the cosmic web in the outskirts of the massive galaxy clusters, focusing on filaments, from 3D gas density maps and 2D Compton-y, X-rays and optical mock-maps that
mimic the properties of known instruments. We investigate the correlation between the presence of filaments and the main properties of galaxy clusters, such as their mass, dynamical state – expressed in terms of the degree of relaxation and hydrodynamical
mass bias – and the filaments’ evolution with redshift. We study the projection effects in the cosmic web identification arising from 3D maps to 2D. Lastly, we compare the skeletons extracted from gas maps with those from mock y and X-rays maps.</div>
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<div style="">Thanks,</div>
<div style="">Joe</div>
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