Dr Matthew Middleton
STFC Ernest Rutherford Fellow, University of Southampton
Title of Research: Supermassive black hole growth - a small-scale solution to a large-scale problem
Accretion onto super-massive black holes (SMBHs) leads to mass and energy being transported from scales comparable to our solar system, to those many times larger than our Galaxy, and has been one of the defining influences in sculpting our observable Universe. My research focusses on the most extreme – and least understood – regime of accretion, one which enabled the rapid growth of SMBHs at high redshift. To explore this, I study local analogues called ultraluminous X-ray sources (ULXs) which contain stellar rather than super-massive compact objects. By understanding the physics occurring in ULXs, we can hope to understand analogous accretion onto high redshift SMBHs and the impact on the early Universe – soon to be glimpsed for the first time with JWST.
As part of international collaborations, I observe ULXs across multiple wavebands (radio – X-rays) and, through applying spectral-timing analysis techniques, we are provided with additional power to reveal the fundamental nature of the accretion flow. The result has been new models and a number of important breakthroughs, including the discovery of the tell-tale signature of winds being launched from ULXs at high speeds, providing unique insights into their nature. The discovery of X-ray pulsations from several ULXs has shown that neutron stars must account for some fraction of the ULX population; determining which ULXs host neutron stars and which host black holes is crucial for making direct comparisons to SMBHs. My team is at the forefront of developing new approaches based on the General Relativistic effect of frame-dragging, which we hope will allow us to both locate the black hole systems and test fundamental physics. Once black hole ULXs have been identified, we will be able to test our understanding of extreme accretion through the application of next-generation spectral-timing models obtained from 3D RMHD simulations using time awarded via DiRAC.
Dr Haixing Miao
STFC Ernest Rutherford Fellow, University of Birmingham
Title of Research: Exploring quantum aspects of gravitational-wave detectors
Ground-based gravitational-wave (GW) detectors including Advanced LIGO and Virgo, which recently made breakthrough discoveries, are kilometre scale laser interferometers with kilogram size mirrors as the test masses. Due to extreme weakness of the GW signal, they are among the most sensitive instruments that we have ever built. It turns out that quantum mechanical effects of light (optical field) and its interaction with the test masses (mechanics) introduces quantum noise that limits the detector sensitivity. On the one hand, we need to understand the optomechanical interaction in the quantum regime—quantum optomechanics, and apply quantum-measurement techniques to improve the sensitivity. On the other hand, we can take advantage of such quantum-limited devices to explore quantum behaviours of macroscopic objects—macroscopic quantum mechanics (MQM).
My research has been focusing on these quantum aspects of GW detectors and quantum optomechanical devices in general. With national and international collaborators, we have investigated different quantum techniques to reduce quantum noise, which leads to new detector configurations. Most recently, by studying the fundamental quantum limit, we have found out that the ultimate sensitivity limit comes from the dissipative processes due to losses present in the optics. The next step is coherently combining different techniques to achieve such an ultimate limit, which informs the design of next-generation GW observatories. For MQM, we are looking into the prospects of using quantum optomechanical devices to explore the quantum nature of gravity in table-top experiments.
Dr Chris Nixon
STFC Ernest Rutherford Fellow, University of Leicester
Title of Research: Accretion disc physics: breaking the symmetries
Accretion discs are a critical component in many astronomical systems: they are the birth sites of stars and planets, and they surround supermassive black holes in active galaxies and quasars. These discs form when gas moves on orbits in the gravity field of a star or black hole, balancing the central gravitational pull with the centrifugal effect of rotation. Angular momentum is transported outwards by the action of a viscosity, allowing most of the gas to spirals inwards. This process turns gravitational potential energy into light that we can observe, and is the most efficient way of extracting energy from ordinary matter. In some systems this can be observed across much of the entire visible Universe. Supermassive black hole accretion can outshine galaxies and significantly affect the hole’s surroundings through energy and momentum feedback. When we observe these systems they always show complex time variability, and theoretical models are now starting to produce plausible mechanisms to explain these phenomena.
My research makes use of the DiRAC high performance computing facilities to model accretion discs using Lagrangian- and grid-based numerical methods. These computer simulations are targeted at understanding different astrophysical systems; from the formation and evolution of protostellar discs aimed at understanding the disc conditions at the point at which planets are starting to form, to the evolution of the stellar debris formed in a tidal disruption event where a star passes too close to a supermassive black hole. In each case the theoretical work is motivated by the latest observational data which routinely provides impetus for new ideas and puzzles to be solved.
Dr Pin Wu
STFC Daphne Jackson Fellow, Queen's University Belfast
Title of Research: Magnetic reconnection in astrophysical plasmas
More than 99% of the visible universe, the stars, galaxies and the matter spread between them, are ionised gas, so-called plasma. Most plasmas can be viewed as magnetic field carrying, electrically conducting fluids. The magnetic fields are highly variable: tangled, twisted, and are continuously pushed together or pulled apart with the plasma flow. When pushed together, oppositely directed components of magnetic field lines can break and subsequently reconnect.
Magnetic reconnection can lead to fierce and stormy releases of energy that drive explosive events such as coronal mass ejections and solar flares. The energetic particle bursts from such storms can damage satellites, harm astronauts, disrupt communications, and in extreme cases shut down power grids. Understanding how reconnection occurs and dissipates energy can help us improve our predictive capability for space weather. Outside our solar system, reconnection also operates in accretion disk, supernova, or in the outflows of active galactic nuclei, pulsars or black holes.
The fundamental questions of reconnection centre on why it occurs so violently fast and what triggers its onset. The difficulty in theoretical efforts are due to the nonlinearity of the problems. The principal computational challenge lies in the need of computing resources necessary to cover all the relevant micro- and macro- scales in three dimensions with the appropriate consideration of boundary conditions. In-situ space borne observations are limited by local measurements. To resolve the whole puzzle, requires a complementary approach, that combines theoretical predictions with experimental measurements.
The first part of my research focuses on analysing observations of reconnection related events in the lower solar atmosphere by NASA's IRIS and SDO space missions. Currently, the primary focus of my research is to simulate laboratory laser driven reconnection using the EPOCH code. The aim is to assist future experiments into emerging field of laboratory astrophysics, and to shed light on reconnection dynamics for astrophysics.
Dr Andreas Schmitt
STFC Ernest Rutherford Fellow, University of Southampton
Title of Research: Dense matter in compact stars
Neutron stars - objects with a mass of 1-2 solar masses and a radius of about 10 km - contain the densest matter in the universe. This ultra-dense matter is very different from ordinary matter on earth: the density in the interior of the star is sufficiently large for the atomic nuclei to overlap, and thus fundamental properties of the strong nuclear force become crucial to understand macroscopic, observable properties of neutron stars. Neutron stars are therefore complex systems that are governed by the theory of the strong nuclear force, Quantum Chromodynamics (QCD).
My research is centred around this "condensed matter physics of QCD", both from a theoretical perspective and from an astrophysical point of view. The theoretical aspects concern for instance the structure of the QCD phase diagram, which is poorly known because even brute force calculations fail in the regime of large baryon densities. One fundamental question is at which density the deconfinement transition occurs and whether it is a discontinuous phase transition. The astrophysical version of this question is whether there is deconfined quark matter in the core of the neutron star or whether the star is made entirely out of nuclear matter. I am addressing this question with various theoretical methods, for instance employing the so-called gauge/gravity correspondence or using effective theories and phenomenological models to describe nuclear and quark matter.
As in usual condensed matter systems, the phase structure of dense QCD is expected to be very rich. Nucleons and quarks can form Cooper pairs similar to electrons in ordinary superconductors. Therefore, neutron stars may host complicated superfluid and superconducting interiors, including magnetic flux tubes and superfluid vortices. I am investigating these phases and their hydrodynamic properties, trying to understand and explain various astrophysical observations, such as pulsar glitches or the cooling behaviour of neutron stars. Understanding microscopic, fundamental physics from neutron stars is an exciting field of research also because of the recent discovery of gravitational waves from a neutron star merger, which opens up new possibilities to improve our knowledge of the condensed matter physics of QCD.
Dr Erminia Calabrese
STFC Ernest Rutherford Fellow, Cardiff University
Title of Research: Precision cosmology from early and late-time surveys
Our best understanding of the origins and evolution of the Universe is driven by observations of the Cosmic Microwave Background (CMB), a relic light that has been travelling for almost 14 billion years since the Big Bang. Over the last two decades, CMB data have led the establishment of a standard model of cosmology, ‘ΛCDM’: we live in a geometrically flat Universe filled with photons, neutrinos, normal baryons and mysterious dark components (dark matter and dark energy). Cosmic structures were seeded by tiny initial density ripples thought to be stretched to cosmological scales during ‘cosmic inflation’ and then grown under gravity. Although supported by many astrophysical and cosmological data, this model is heavily incomplete from a theoretical point of view: did cosmic inflation really happen? If yes, what drove it? What is the nature of dark matter and dark energy? What is the absolute mass scale of neutrinos? My research spans theoretical work and statistical data analysis of state-of-the-art CMB data to answer these fundamental questions.
The CMB has been recently mapped with unprecedented precision by the ESA’s Planck satellite. The final Planck data provide strong support to the ΛCDM model and constrain its basic parameters to sub-percent accuracy. The next steps in CMB cosmology are now driven by improved measurement of CMB polarization from ground-based telescopes, including ACT (the Atacama Cosmology Telescope). Alongside CMB data, observations of galaxies’ shape and distribution test the physics of the local Universe (i.e. of the last 10 billion years). Combining CMB and galaxy data is crucial to reduce the impact of instrumental and astrophysical systematics and to distinguish physical processes which would be otherwise degenerate.
As part of my ERF work, I contribute to the analysis of the Planck data and lead data characterization and scientific exploitation of ACT CMB data, alone and in combination with galaxy data.
Dr Andrew Hillier
STFC Ernest Rutherford Fellow, University of Exeter
Title of Research: Magnetism and Fluid Flows in our Solar-Planetary Environment
Solar prominences (otherwise known as filaments) are one of the most fascinating structures in the solar atmosphere. They can be observed as cloud-like features that are comprised of relatively cool plasma (10,000 K) embedded in the hot corona (1,000,000 K) which is supported against gravity by the magnetic fields that permeate the solar atmosphere. The eruption of prominences lead to coronal mass ejections (a collection of mass and magnetic field violently ejected from the Sun) which are of great importance for their space weather effects.
The launch of the Hinode satellite in 2006 followed by the Interface Region Imaging Spectrograph (IRIS) in 2013 provided new eyes with which to look at the solar atmosphere, and the wavelengths of light (some of which are emitted by plasma around 10,000K) under study by these missions made them perfect for observing prominences. These observations have revolutionised our understanding of prominences, showing that prominences can be highly dynamic across all their observable spatial and temporal scales, making them a wonderful laboratory to study magnetised fluid dynamics. However, in many cases the physical processes behind these dynamics are still to be made clear. My fellowship is about both theoretically and observationally understanding these dynamics and determining their effects across the observed scales of the prominence and beyond.
A key component of my work in determining how instabilities and other processes can create these wonderful dynamics comes from the fact that prominence plasma mainly consists of neutrally charged atoms that cannot directly interact with the magnetic field. The way these neutral species can experience magnetic forces is indirectly, by colliding with charged species resulting in an exchange of momentum. So as part the turbulent motions in prominences driven by magnetic forces, it is important to comprehend how the neutrals respond, and how this changes, for example, the heating in the plasma. However, my focus is not only on these, relatively speaking, small spatial and temporal scales. The impact of all the observed dynamics may be important in determining how the prominence system can slowly evolve to become unstable and erupt (i.e. through a huge number of tiny motions producing a big change), and I am also looking into this process.
Dr Timothy Davis
STFC Ernest Rutherford Fellow, Cardiff University
Title of Research: The cycle of life, death and rebirth in massive early-type galaxies; star formation, black holes and feedback
My research focuses on understanding the most massive galaxies in the local universe. These objects are made up of billions of old stars, have red optical colours, and are generally thought to be free of cold gas - the fuel for new stars. Thus they are often described as ”red and dead”. Astronomers still don’t know what caused these galaxies to die, or if they can come back to life again.
One of the ways astronomers think that massive galaxies become ”red and dead” is due to supermassive black-holes. These enigmatic objects are ubiquitous, and strongly linked to galaxy formation, as they seem to grow in step with their galaxy host. In order to understand the role of black holes in the formation of galaxies I have developed a new technique to measure their masses, by tracing the motions of molecular gas clouds swirling around them. As an Ernest Rutherford fellow, one of my main activities is leading a team of researchers using extremely high spatial resolution data from ALMA (the Atacama Millimetre/Submillimetre Array) to reveal the dark monsters lurking at the hearts of nearby galaxies.
Massive galaxies, like the ones I study, don’t have to stay ”red and dead” forever. They can come back to life if material from dying stars cools, becoming fuel for a new generation of stars. They can also merge with other small galaxies and steal their gas. As part of my research I study these processes, revealing that around 1/4 of the massive ”red and dead” galaxies around us today are currently in the process of being reborn. These regenerated galaxies don’t seem to be using this new fuel very effectively, however, and form stars very inefficiently when compared to galaxies like our own Milky Way. As a Rutherford fellow I aim to find out why this is happening, and what this can tell us about the physics controlling star formation across the universe.
Dr Kate Maguire
Lecturer and STFC Ernest Rutherford Fellow, Queen's University Belfast
Awarded ERF 2015
Title of Research: Understanding cosmological probes: constraining the progenitors and diversity of Type Ia supernovae
Supernovae are the extremely bright explosions resulting from the violent deaths of stars. They have a major influence on many areas of astrophysics but they are perhaps best known for their use in measuring distances in the Universe. The homogenous nature of a particular type of exploding star, Type Ia supernovae, led to the discovery of the mysterious cosmological quantity, dark energy, that we now know makes up ~70% of the mass-energy of the Universe but whose origin remains unknown.
Future state-of-the-art surveys (e.g. the European Space Agency mission, Euclid and the Large Synoptic Survey Telescope, LSST) are being designed to constrain theories of dark energy using larger supernova samples. However, to distinguish between these theories, it is very important to understand the elusive properties of the supernovae themselves. This is the aim of my Ernest Rutherford fellowship.
Surprisingly despite their use in precision measurements of dark energy, we still do not understand the stellar systems that explode as Type Ia supernovae. Key questions to be addressed include: 'Is there more than one way to make a Type Ia supernovae?', 'How exactly do they explode?' and 'How do the properties of the galaxies within which they explode affect their explosions?'.
My aim is not only to unveil the stellar systems that explode as Type Ia supernovae but also to understand how their properties may evolve throughout the Universe. In the earlier Universe, galaxies had different properties to those forming today, which has been shown to have a subtle, but measurable, influence on the properties of Type Ia supernovae.
I am using data from some of the world's largest telescopes at the European Southern Observatory (ESO) in Chile, combined with theoretical modelling of their explosions, to understand the origin of Type Ia supernova and constrain their diversity. This project is very timely with the potential for significant breakthroughs in Type Ia supernovae research to be made before the next-generation transient survey, LSST, begin in ~2021.
Dr. Darren Price
Senior Lecturer and STFC Ernest Rutherford Fellow, University of Manchester
Awarded ERF 2015
Title of Research: Using the LHC as an electroweak boson collider: a novel laboratory for dark matter, neutrino, and new electroweak phenomena
The Large Hadron Collider (LHC) at CERN collides protons together around one billion times per second in the highest energy ever produced in the laboratory. The ATLAS experiment collects the vast amounts of data from the particles produced in these collisions. Particle physicists such as myself sift through this data to make sense of the collisions, and investigate the particles that make up our Universe and the interactions between them.
Protons are composite objects, made from a complex mix of quarks and gluons held together by the strong force. At the LHC the majority of proton collisions producing particles we see in our detectors are due to collisions between gluons or quarks inside the two protons. But what if undiscovered particles don't interact directly with the colliding quarks and gluons? Or only do so extremely rarely? In such circumstances it is very difficult to see the subtle signatures of these new particles amongst the deluge of data from far more common interactions.
In fact, many of the mysteries we aim to solve may be related to the electroweak force rather than the strong force: what is dark matter, the substance that appears to make up 85% of the mass of our Universe -- is it a weakly-interacting particle? Why is the mass of the neutrino so much smaller than that of the other known fundamental particles? Is the discovered Higgs boson alone in providing masses to the fundamental particles? To answer these questions, my research focuses on isolating the rare processes where the quarks from incoming protons each emit weak bosons (carriers of the electroweak force) that collide instead of the quarks themselves. This process, known as vector boson fusion, effectively turns the LHC from a proton collider into an electroweak boson collider!
My research initially focused on developing techniques to reliably and precisely extract the signatures of these rare events from typical proton--proton collisions. The success of these techniques enabled first observation and accurate measurement of predicted electroweak processes that occur once in every hundred million million collisions at the LHC. Building on this, my research has now extended into the first measurements of collisions producing invisible particles (known and unknown!) through electroweak interactions, such as dark matter. As we are searching for the unknown, a key aspect to the measurement design and the data released is that it is easily preserved and easily reinterpretable, so that new theories coming along in the future can be readily tested against existing data. With more LHC collisions this year, we will soon have data to extend this approach to search for other unexpected phenomena, providing new insights into our Universe.
Dr Izaskun Jiménez-Serra
Lecturer and STFC Ernest Rutherford Fellow, Queen Mary University of London
Awarded ERF 2014
Title of Research: Massive Star Formation with New Generation Interferometers
Massive stars - stars with masses larger than 8 times the mass of the Sun - are rare in our Galaxy. However, they dominate the energetics and feedback of galaxies shaping their structure and largely impacting on their evolution. Massive stars are also the source of heavy elements, essential in metabolic processes in living organisms. Understanding the processes that lead to the formation of massive stars is therefore crucial to determine their role not only in galaxy structure and evolution, but also in the production of heavy elements key for life.
Astronomical facilities operating at infrared wavelengths such as the Spitzer Space Telescope and the Herschel Space Observatory, have revealed the earliest stages of massive star formation characterized by filamentary structures of dust and molecular gas viewed as shadows against the background of our own Galaxy. Theoretical models of molecular cloud formation predict that these filaments could form in giant collisions of gentle molecular gas flows, which would then trigger the formation of massive stars and star clusters. However, little observational evidence does exist supporting this scenario.
To unveil the physical processes that lead to the formation of massive stars, I observationally cover all stages of early massive star birth from the initial conditions in molecular filaments, to the later stages where massive stars are embedded in hot and dense cocoons of molecular gas and dust. For this reason, I use molecules (and their chemistry) as probes of the physical mechanisms involved in this process. Since the regions where massive stars form are distant from us, new generation interferometers such as the Atacama Large Millimetre/sub-millimetre Array (ALMA), and in the future the Square Kilometre Array (SKA), are needed to image their internal physical and chemical structure with exquisite detail. This research will advance our understanding of how massive star formation takes place in our Galaxy, and of how it impacts galaxy structure and evolution.
Dr Simon Dye
Associate Professor in Astrophysics, School of Physics and Astronomy, University of Nottingham
Awarded ERF 2015
Title of Research: The Evolution of Mass and Light in Galaxies
Over the last couple of decades, the question of how large scale structure in the Universe formed and evolved has been one of the most fiercely contested topics in astrophysics. Galaxies are the Universeʼs building blocks and as such are fundamental to a mature and complete understanding of the processes governing the Universeʼs construction.
Despite this, we still lack a satisfactory picture of how galaxies themselves are built and how they evolve. One of the primary reasons for this is that existing work to quantify the total mass structure of galaxies has been limited to relatively small samples of galaxies in the nearby Universe.
Strong gravitational lensing is a naturally occurring phenomenon which can be exploited to act as a powerful probe of the mass in galaxies.
Galaxy-galaxy lens systems occur when the gravitational field of a galaxy located mid-way along the line of sight from Earth to a very distant galaxy focuses the distant galaxy's light towards Earth. In this way, the nearer galaxy acts like a lens, giving us a highly magnified but highly distorted view of the distant galaxy. Analysis of the lensed image of the distant galaxy allows detailed study of not only the distant galaxy itself, but also the distribution of dark and baryonic mass in the nearer lensing galaxy.
Dr Dye's work concentrates on using strong galaxy-galaxy lens systems to help disentangle the complex physical processes at play in the formation of galaxies. In particular, he is analysing an exciting new large sample of such lenses uncovered by the Herschel Space Observatory. Observing at sub-millimetre wavelengths means that both the lensing and lensed galaxies detected lie at significantly larger distances on average than existing galaxy-galaxy systems discovered at optical wavelengths. Because they are more distant and because the speed of light is finite, a snapshot of an earlier phase in their lifetime is obtained. Study of the sample is made possible by the fantastic high resolution imaging capability of the Atacama Large Millimetre/sub-millimetre Array which, in combination with the intrinsic magnification caused by the gravitational lensing, affords a highly detailed view of the structure and formation mechanisms of the lensed galaxies when they were younger. The work is therefore helping us gain new insights into the formation of galaxy structure at a time when the Universe was undergoing much more dramatic evolution.
|Dr James Aird||University of Leicester|
|Dr Fabio Antonini||University of Surrey|
|Dr Patrick Antolin||University of St Andrews|
|Dr David Alonso||Cardiff University|
|Dr David John Armstrong||University of Warwick|
|Dr Matthew Auger||University of Cambridge|
|Dr Simon Badger||Durham University|
|Dr Sarah Badman||Lancaster University|
|Dr Robert Burston||University of Bath|
|Dr Mikhail Bashkanov||University of York|
|Dr Erminia Calabrese||Cardiff University|
|Dr Sarah Casewell||University of Leicester|
|Dr Christopher Chen||Queen Mary University of London|
|Dr Timothy Davis||Cardiff University|
|Dr Richard Davison||University of Cambridge|
|Dr Oscar Joao Campos Dias||University of Southampton|
|Dr James Dobson||University College London|
|Dr Simon Dye||University of Nottingham|
|Dr Gabriel Facini||University College London|
|Dr Robert Fear||University of Southampton|
|Dr Andreu Font-Ribera||University College London|
|Dr Liam Gaffney||University of Liverpool|
|Dr Masanori Hanada||University of Southampton|
|Dr Lucian Harland-Lang||University of Oxford|
|Dr Andrew Hillier||University of Exeter|
|Dr Robert George Izzard||University of Surrey|
|Dr Caitriona Jackman||University of Southampton|
|Dr Matthew Kenzie||University of Cambridge|
|Dr Claudia Lederer-Woods||University of Edinburgh|
|Dr David Long||University College London|
|Dr Kate Maguire||Queen's University of Belfast|
|Dr Mikako Matsuura||Cardiff University|
|Dr Christopher McCabe||King's College London|
|Dr Paul McFadden||Newcastle University|
|Dr Haixing Miao||University of Birmingham|
|Dr Matthew Middleton||University of Southampton|
|Dr Ryan Milligan||University of Glasgow|
|Dr Alexander Mitov||University of Cambridge|
|Dr Christopher Nixon||University of Leicester|
|Dr Darren Price||The University of Manchester|
|Dr Steven Parsons||University of Sheffield|
|Dr Nicholas Ross||University of Edinburgh|
|Dr Giuseppe Ruggiero||Lancaster University|
|Dr Helen Russell||University of Cambridge|
|Dr Andreas Schmitt||University of Southampton|
|Dr Pat Scott||Imperial College London|
|Dr Blake Sherwin||University of Cambridge|
|Dr Colin Snodgrass||University of Edinburgh|
|Dr Rowan Smith||The University of Manchester|
|Dr Romain Tartese||The University of Manchester|
|Dr Rita Tojeiro||University of St Andrews|
|Dr David Vegh||Queen Mary University of London|
|Dr John Veitch||University of Glasgow|
|Dr Daniel Verscharen||University College London|
|Dr Dimitri Veras||University of Warwick|
|Dr Mika Vesterinen||University of Warwick|
|Dr Dominic Walton||University of Cambridge|
|Dr Nicholas Wardle||Imperial College London|
|Dr Julie Wardlow||Lancaster University|
|Dr David Weir||University of Nottingham|
|Dr Nicholas Wright||Keele University|
|Dr Nicholas Zachariou||University of York|
|Dr Svitlana Zhukovska||University of Exeter|
On 5 March 2018 STFC held its second Introductory Workshop for newly appointed Ernest Rutherford Fellows. Thank you to those who participated in the event.
The agenda together with links to the speaker presentations are now available to view.
Last updated: 06 June 2019