The relationship between galaxy environment and the quenching of star formation
Publication Date
March 15, 2019
Creator
Abstract
In this thesis, we explore the impact of environment on the star formation properties of galaxies across 6.5 Gyrs of cosmic time, corresponding to the redshift range 0.5
We characterise galaxy environment using two different methods. The first method is used at low redshift (z<1.0) and is based of a friends-of-friends algorithm, which allows us to identify overdensities (galaxy clusters and groups) in the UDS field. This method was thoroughly optimised to run on the UDS data, and the output tested using the extensive spectroscopic redshifts that are available in the UDS field, and by comparing to previous overlapping cluster studies. The method also generates a field sample with the same redshift distribution as the cluster sample, allowing for the comparison between these two environments.
A second method, based on fixed apertures, was also implemented in order to study the environmental trends in a more self-consistent way across the broad redshift range 0.51 Gyr). Of the cluster galaxies in the stellar mass range 9.010^10.3Msun show slightly different environmental trends. At low stellar masses there is an enhancement of both star-forming galaxies with low SSFRs and PSBs in dense environments at z<1.5. In contrast, at higher masses the low-SSFR galaxies are strongly depleted in dense environments since z~1.75. We also find that massive galaxies are more sensitive to environment, i.e. their star-forming properties are more affected than those of low-mass galaxies at the same environmental overdensity level. From this we conclude that the action of secular processes in massive galaxies might be aiding the environmental effects, leading to faster quenching. In other words, secular and environmental processes may join forces to drive the evolution of the most massive galaxies in the distant Universe.
Item Type
ethesis
Thesis Type
PhD
Supervisors
Subjects (LC)
Associated Schools / Departments
School of Physics and Astronomy
eprints ID
55763
UoN Repository URI
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