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<span style="font-size: 14px;">Hi all,</span>
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This week’s lunch talk will be given by Rhys Jordan, and will take place on Thursday 26th February at 1pm in A113. Title and abstract below.</span></div>
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<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;"><b>Title:</b> Infalling groups revealed by machine learning</span></div>
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<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;"><b>Abstract:</b></span></div>
<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;">Galaxy evolution is strongly influenced by its environment, as evidenced by the prevalence of blue, star-forming galaxies in the field compared to the red, quiescent populations
that dominate galaxy clusters. Increasing evidence suggests that a significant fraction of this transformation occurs prior to cluster accretion, through so-called pre-processing in galaxy groups and filaments. Understanding where and when this pre-processing
occurs is therefore essential for disentangling the environmental influence on galaxy evolution.</span></div>
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<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;">In this talk, I present the current development of a new group-identification framework designed to detect galaxy groups in cluster infall regions. Our approach combines
machine learning with an adapted Friends-of-Friends algorithm, optimised for application to spectroscopic surveys of galaxy clusters. Using mock observations from simulated data, we recover approximately 80% of the true groups across the infall region. When
identifying galaxies belonging to specific groups, we achieve an average completeness of 60% and purity of 75%. This balance between completeness and purity enables robust identification of infalling groups along with their members. Importantly, the framework
does not bias the stellar mass functions of either the group central or member populations. It therefore provides a powerful foundation for studying how galaxies in infalling groups transition into the cluster population.</span></div>
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<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;">Thanks,</span></div>
<div class="elementToProof" style="color: rgb(0, 0, 0);"><span style="font-size: 14px;">Joe</span></div>
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