[Astro] Lunch Talk

[Michael Anderson Jennings]

Hi Everyone,

Reminder of the lunch talk today at 1pm in A113.

If anyone wants to meet Harry before the talk we will be going for lunch at 11:45am, meeting in the CAPT foyer.

Also, the paper the talk is based on has been put on the Arxiv (https://arxiv.org/pdf/2412.07834) this morning and you might notice our very own Joe Butler is one of the co-authors.

Thanks,
Mikey


Mikey Anderson Jennings
Astronomy PhD Student
University of Nottingham
Centre for Astronomy and Particle Theory

________________________________
From: Michael Anderson Jennings
Sent: 09 December 2024 12:05 PM
To: astro at nottingham.ac.uk <astro at nottingham.ac.uk>
Cc: h.stephenson at lancaster.ac.uk <h.stephenson at lancaster.ac.uk>
Subject: Lunch Talk

Hi Everyone,

This week's lunch talk will be the last of this calendar year and will be given by an external speaker Harry Stephenson (Lancaster University), it will be on Thursday at 1pm in A113. Title and Abstract are below.

Anisotropic Quenching in 𝒛∼𝟎.𝟒 clusters: AGN or Large Scale Structure

The mechanisms that suppress star formation in cluster galaxies are numerous, and analysing their impact is crucial to understanding galaxy evolution. Recently, studies have shown that the quenching of satellite galaxies is dependent on their orientation angle to the brightest cluster galaxy (BCG), whereby galaxies along the BCG major axis have significantly reduced star formation compared to those that reside along the minor axis. This has been dubbed “anisotropic quenching” or “angular conformity”. To probe this anisotropic quenching signal, we used Subaru data of Cluster Lensing And Supernovae survey with Hubble clusters to analyse the colour of ≈ 7,000 satellites, and passive galaxy fractions, at z = 0.2 – 0.5 as a function of their orientation angle from the BCG.I will discuss our detection of an anisotropic quenching signal out to cluster-centric radii of 3R200 in both satellite colour and passive galaxy fraction against orientation angle that peaks along the major axis. The amplitude of this signal is the largest observed in studies of anisotropic quenching. We find a peak in the amplitude at ≈ 1.25R200 for both satellite colour and passive galaxy fraction. We also investigated if the increased quenching along the major axis is a reflection of the increased density of galaxies. We find that passive galaxy fractions are significantly higher along the major axis for fixed values of local density, suggesting another mechanism is preferentially acting along the major axis. We believe that this signal is caused by preprocessing in filaments that feed satellites into the cluster along the BCG major axis.

Thanks,
Mikey

Mikey Anderson Jennings
Astronomy PhD Student
University of Nottingham
Centre for Astronomy and Particle Theory

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