Masters by Research Degrees in Astrophysics

The Astrophysics Group has a thriving programme for research masters degrees (MSc) for self-funded students. Masters students carry out an independent research project with support from a member of academic staff which is assessed on the basis of the examination of a thesis after one year of research and up to two years of writing up (part time study is also possible). Students are expected to attend advanced undergraduate and postgraduate lecture courses in relevant subjects, and follow courses of directed reading, but the emphasis of the programme is on research rather than the taught element.

Several possible or recent MSc projects are given below, and other projects are available in all of our research areas. If you are interested in such a degree, you are urged to contact Dr Andy Young as far as possible in advance of the start of the academic year in October.

Near-Field Cosmology and Galaxy Evolution

Compact groups of galaxies offer unique laboratories to study galaxy-galaxy interaction, due to their low velocity dispersion compared to the larger galaxy clusters. In this project we will use the new catalogue (McConnachie et al. 2009) of compact galaxy groups from the Sloan Digital Sky Survey (SDSS - Data Release 6) to explore the impact of such interactions on galaxy morphology, star formation etc. This will involve studies of both the imaging and spectra available in SDSS for a large number of the ~3000 compact groups in the catalogue. The student will gain experience in photometry, analysis of spectra, and the use of large-scale astronomical databases, which will prove useful in their future studies.

Dwarf Galaxies in the HST Treasury Survey of the Coma Cluster

The HST Treasury Survey of the Coma Cluster has obtained deep, high resolution images of large areas of the Coma Cluster, the closest very massive galaxy cluster. We have several projects concerned, generally, with the dwarf galaxy content of the cluster and evolutionary processes which affect the dwarfs in this dense environment. In addition we have a specific project to explore what are called post-starburst galaxies and the populations of star clusters which may form in these bursts, thought often to be induced by close interactions and mergers.

Black Holes: Reflection spectra produced by flares above an accretion disks

This is a theoretical and numerical project to compute the time-dependent X-ray spectrum produced by X-ray flares above an accretion disk. The project requires integrating photon paths through the Kerr metric from point-source flares at arbitrary locations above the accretion disk to calculate the flux incident on the disk, and from the observer to the accretion disk to determine what will be observed. The purpose of this project is to produce a general purpose model that can be incorporated into computer programs used to fit X-ray observations of black hole accretion disks. The project is theoretical and numerical, and a knowledge of general relativity (e.g., the Kerr metric) is required.

Black Holes: Iron line emission from accretion disks with misaligned jets

The bipolar jets produced by accreting compact objects can generate intense X-ray radiation. These X-rays will illuminate the accretion disc, and produce an iron fluorescence line. Previous calculations of this phenomenon have assumed that the accretion disc rotation axis and jet axis are aligned. If these are misaligned, it is possible that the X-ray illumination of the disc is enhanced and hence the iron fluorescence line is also enhanced. The objective of this theoretical and computational / numerical project is to calculate the iron line produced by accretion discs illuminated by a misaligned jet.

Optimum Sunyaev-Zel'dovich Effect Mapping

This project would be related to the observations we're currently planning with the new array receiver on the Torun 32-m telescope in Poland. With this system we are planning to make some maps of the structures of extended radio sources (which are fairly bright), and of the Sunyaev-Zel'dovich (SZ) effects of distant clusters of galaxies (which are very faint). The SZ effect data can be used to find where hot baryons are located in the Universe, but to be effective we have to be able to construct extremely sensitive images from the mapping data. This is difficult since we are observing through a time-variable atmosphere, and the purpose of the project is to investigate a number of possible mapping techniques to decide which will be best, and then to use it to make some maps. The project will involve learning about how radio telescopes work, and doing some coding to calculate the effectiveness of the mapping methods and reduce the data when they come in.

Cluster Magnetoacoustic Waves

As galaxies move through the atmospheres in clusters of galaxies they must emit long-wavelength magnetoacoustic waves. These can propagate through the cluster atmosphere, and will dissipate to cause heating. The question of cluster heating is of considerable importance: without some heat source, perhaps this one, cluster atmospheres would undergo collapses within a Hubble time, generating hypermassive galaxies. This project will be theoretical (and likely computational), and should produce an interesting short paper within the year.

The Evolution of Galaxy Clusters

Clusters of Galaxies are highly luminous X-ray sources, allowing them to be studied observationally out to high redshifts. Such studies have given conflicting results on the evolution of galaxy cluster properties, and there is debate in the literature as to whether clusters obey the simplest model for their evolution or if additional factors are present. In this project we will investigate the evolution of the X-ray properties of galaxy clusters using several large samples at different redshifts to properly include selection biases in our analysis. The project will consist of analysis of large amounts of observational data, and statistical treatment of the results, including sample selection biases.

Fractal Galaxy Clusters

Simple models predict that galaxy clusters should have fractal-like behaviour, with low mass clusters being identical to scaled down versions of high mass clusters. However, observations show that this is not the case, and give evidence for extreme physical processes at work in clusters (such as mergers, active galaxy energy input, and runaway cooling) that break this self-similar scaling. This project will be an observational study of low mass clusters, where the similarity breaking is found to be the strongest, in order to better understand the differences from fractal behaviour, and their causes.

For further information about the School of Physics or research studentships, or for application materials, please contact Dr Andy Young

  Dr Andy Young
  School of Physics
  University of Bristol
  Tyndall Avenue
  Bristol BS8 1TL
  U.K.

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