Dr John StottSenior Lecturer in Astrophysics
My research concentrates on distant star-forming galaxies and the evolution of the members of rich galaxy clusters. I am co-PI of the QSO Sightline And Galaxy Evolution survey (QSAGE), a 96 orbit Cycle 24 Hubble Space Telescope program. QSAGE uses the light from distant accreting black holes to probe the gas in the outskirts of galaxies, in order to discover why galaxies were forming stars at a much higher rate in the past and the nature of feedback processes. I am a core member of the KMOS Redshift One Spectroscopic Survey (KROSS) a resolved Halpha survey of 800 typical star-forming galaxies at redshift 1. An up to date list of my publications on NASA ADS can be found here and my Google Scholar page is here
PhD Supervision InterestsGas and galaxies at cosmic noon:
The majority of the stars in the Universe were formed in an active period 7 to 11 billion years ago, an epoch known as ‘cosmic noon’. The reasons for this enhancement in star formation and its subsequent decline to the present day are not fully understood and so this is a major area of galaxy evolution research. Galaxies are governed by competing physical processes: 1. the fuelling of star formation by gas accreted from the cosmic web and 2. the quenching of star formation by feedback from supernovae and supermassive black holes. Their environment also plays an important role with galaxies in dense clusters quenching at early times.
This PhD project will use spectroscopy and imaging from Hubble Space Telescope, WHT-WEAVE and VLT-KMOS to study the conditions of the gas within galaxies and the gas that surrounds them (the circumgalactic medium) in order to understand the balance of star formation fuelling and feedback at cosmic noon. The results of this project will be physically interpreted through comparison with the outputs from state-of-the-art cosmological simulations of galaxy formation.Galaxy clusters in the Big Data era with LSST:
Galaxy clusters are the largest gravitationally bound objects in the Universe, consisting of tens to thousands of galaxies within a relatively small volume. They are used extensively as laboratories for galaxy evolution, as they contain galaxies that have experienced a similar environment and processes over many billions of years. They are also key cosmological indicators with the evolution of the number of galaxy clusters of a given mass being very sensitive to the Dark Matter content of the Universe. Because of their importance for both astrophysics and cosmology it is desirable to obtain large, well understood samples of galaxy clusters over a range of redshifts. The Legacy Survey of Space and Time (LSST, https://www.lsst.org/) is an imaging survey performed with the Rubin Observatory that will discover thousands of new galaxy clusters, providing such a sample. It will image the entire southern sky with an 8.4m telescope every few nights for 10 years, producing 200 petabytes of imaging data. This will be the state-of-the-art for optical surveys for many years to come.
This project aims to further develop pre-existing algorithms and machine learning code to identify large numbers of distant galaxy clusters within the LSST survey. These algorithms will be run on existing comparable, but smaller area surveys, and the early-phase of LSST that will begin operation in 2022. The algorithms will be designed so that they can be scaled-up to deal efficiently with the full size of the main LSST survey. The cluster samples generated here will also be used to study the evolution of galaxies in dense environments and potentially cosmology.
These PhD projects represent just two component of the research performed by the wider Astrophysics group at Lancaster University. Our PhD projects are offered on a competitive basis and are subject to availability of funding.
Lancaster University: Observational Astrophysics PATT grant 2018-2020
01/10/2018 → 30/09/2020
Lancaster University Astrophysics
01/04/2017 → 31/03/2018
National Astronomy Meeting 2019
Participation in conference
- DSI - Foundations
- Observational Astrophysics