The Evolution of Galaxies in Proto-clusters
Publication Date
July 26, 2023
Creator
Abstract
In this thesis, I report on my work on galaxy evolution in proto-clusters. In Chapter 1, I describe previous knowledge about clusters and proto-clusters of galaxies. The next three Chapters correspond to three different projects I have completed during my PhD that are connected to the topic of galaxy evolution in proto-clusters.
In Chapter 2, I quantify the relative importance of environmental quenching versus pre-processing in z~1 clusters by analysing the infalling galaxy population in the outskirts of 15 galaxy clusters at 0.810^11 M☉ were quenched prior to infall, whilst up to half of lower mass galaxies were environmentally quenched after passing the virial radius. This means most of the massive quiescent galaxies in z~1 clusters were self-quenched or pre-processed prior to infall. In Chapter 3, I report on my work on intracluster light in proto-clusters at z~2. In contrast to theoretical expectations, I report on the detection of intracluster light within two proto-clusters at z=2 using deep HST images. I use the colour of the intracluster light to estimate its mass-to-light ratio in annuli around the brightest cluster galaxies (BCG), up to a radius of 100 kpc. I find that 54±5% and 71±3% of the stellar mass in these regions is located more than 10 kpc away from the BCGs in the two proto-clusters. This low concentration is similar to BCGs in lower redshift clusters, and distinct from other massive proto-cluster galaxies. This suggests that the proto-cluster BCGs have already experienced a special merger history similar to their lower redshift counterparts. We compare these observations to the Hydrangea hydrodynamical galaxy cluster simulations. In contrast to semi-analytic models, they predict that intracluster stars are a generic feature of massive halos since at least $z=2$. This implies that intracluster light is a natural consequence of hierarchical structure formation. Over Chapter 4, I report on my work on the luminosity function and Dn4000 measurements of proto-cluster galaxies at 1.3
In Chapter 2, I quantify the relative importance of environmental quenching versus pre-processing in z~1 clusters by analysing the infalling galaxy population in the outskirts of 15 galaxy clusters at 0.810^11 M☉ were quenched prior to infall, whilst up to half of lower mass galaxies were environmentally quenched after passing the virial radius. This means most of the massive quiescent galaxies in z~1 clusters were self-quenched or pre-processed prior to infall. In Chapter 3, I report on my work on intracluster light in proto-clusters at z~2. In contrast to theoretical expectations, I report on the detection of intracluster light within two proto-clusters at z=2 using deep HST images. I use the colour of the intracluster light to estimate its mass-to-light ratio in annuli around the brightest cluster galaxies (BCG), up to a radius of 100 kpc. I find that 54±5% and 71±3% of the stellar mass in these regions is located more than 10 kpc away from the BCGs in the two proto-clusters. This low concentration is similar to BCGs in lower redshift clusters, and distinct from other massive proto-cluster galaxies. This suggests that the proto-cluster BCGs have already experienced a special merger history similar to their lower redshift counterparts. We compare these observations to the Hydrangea hydrodynamical galaxy cluster simulations. In contrast to semi-analytic models, they predict that intracluster stars are a generic feature of massive halos since at least $z=2$. This implies that intracluster light is a natural consequence of hierarchical structure formation. Over Chapter 4, I report on my work on the luminosity function and Dn4000 measurements of proto-cluster galaxies at 1.3
Item Type
ethesis
Thesis Type
PhD
Supervisors
Subjects (LC)
Associated Schools / Departments
School of Physics and Astronomy
Author URL(s)
eprints ID
73627
UoN Repository URI
Except where otherwise noted, this item's license is described as
File(s)![Thumbnail Image]()
Name
PhD_THESIS.pdf
Type
Full-text
Description
Examined
Size
14.57 MB
Format
Adobe PDF
Checksum (MD5)
180e40c87513c7f55b2459d39299a248