PhD Projects by Prof. Mathew Page

The growth of massive black holes over cosmic time

Prof. Mathew Page

All massive galaxies today contain supermassive black holes at their centres. The black holes grew by accreting material from their surroundings, shining as quasi-stellar objects (QSOs) and emitting copious X-rays as they did so. Their heyday was during the epoch of galaxy formation, when the Universe was about a third of its present age. Black holes are now a central part of the paradigm for galaxy formation, and are thought to have shaped their host galaxies through radiation, winds and relativistic outflows. The history of black hole growth is thus intimately connected to the evolution of our Universe. The aim of this project will be to investigate the build up of black holes over cosmic time through construction of X-ray luminosity functions of QSOs, using a new technique in which the X-ray energy band of interest tracks the redshift of the QSOs. The objective is to produce luminosity functions in a consistent rest-frame X-ray energy band over the majority of cosmic time. The project will make extensive use of the large range of X-ray surveys which have been carried out using the XMM-Newton and Chandra X-ray observatories. By fixing the X-ray energy band in the rest-frame, the need to model the redshift-dependence of X-ray absorption from material surrounding the black holes will be eliminated, so that the most reliable description of the history of black hole growth so far can be derived.

Deep X-ray Image Xray Luminosity Function

Gamma-ray burst astrophysics

Prof. Mathew Page

Universe since the Big Bang. For around 30 years after their discovery in the late 1960s, gamma-ray bursts were one of astronomy's biggest mysteries. The locations of gamma ray bursts were finally localised with enough precision to search for X-ray and optical afterglows, and identify the galaxies in which they originate, in the late 1990s. In 2004, NASA's Swift observatory was launched, which localises gamma ray bursts autonomously as they are happening, and slews within 90 seconds to bring its Optical/UV Telescope and X-ray Telescope to capture the afterglow within a few minutes of the burst. We now know that long gamma-ray bursts (with durations longer than 2 seconds) occur in the hypernova explosions that end the lives of massive stars, and that the short gamma-ray bursts are likely to come from the merging of neutron star binaries. The physics of the explosion and subsequent afterglow are hot topics of debate. Swift, together with ground based telescopes and other space observatories, are providing a wealth of data on gamma ray bursts and their afterglows. The Optical/Ultraviolet Telescope (UVOT) onboard Swift was designed and constructed at MSSL, and we host an operations team which plays a major role in the Swift observatory, analysing the gamma-ray burst data as it comes down from Swift.

We are looking for a PhD student to work alongside our operations team in studying gamma-ray bursts and to utilise the large body of UVOT data to further our understanding of the physics of these phenomenal explosions: how they are powered, how the relativistic blastwave deposits its energy into the surrounding medium, the environments in which gamma-ray bursts occur, what the progenitor stars could be, and what gamma-ray bursts tell us about the cosmic history of star and galaxy formation. The student will examine correlations between the gamma-ray and optical energetics, building on the correlation we recently found between the brightness of the afterglow and the speed with which it fades (Oates, Page et al. 2012, MNRAS 426, L26). The PhD will also involve real-time investigation and follow up of gamma-ray bursts, starting within the first few minutes of a burst being detected with Swift. 

Swift Spacecraft

The Swift spacecraft.