Computer simulation shows the seeding of super-massive black holes is a natural by-product of the formation of the cosmic web.
Super-massive black holes which are billion of times more massive than the sun have been detected at the centres of galaxies across the Universe. Most famously our own Milky-Way hosts a super-massive black hole a few million times the mass of the sun at its centre. Despite all this evidence for their existence, the origin of super-massive black holes is an unsolved open question in astrophysics.
A team of international researchers including Professor Sadegh Khochfar from the School’s Institute for Astronomy used 2 million processor hours on super-computers in the UK to show for the first time that that the seeding of super-massive black holes is a natural by-product of the formation of the cosmic web in a Universe dominated by dark energy and cold dark matter. The results provide an answer to the long-standing question on the seeds of super-massive black holes and why they are so ubiquitous in galaxies.
The collaboration setup cosmological simulations that followed the evolution of dark matter and gas in the Universe as it collapses along the network of cosmic filaments. As gas moves along the filaments it reaches the most massive dark matter haloes present in the Universe, which sit at the crossing of filaments. In the present study, four filaments converge onto the dark matter halo under investigation and provide cold and dense gas streams that collide at the centre of the halo and form turbulent gaseous clouds. The ability of this gas to further collapse and form stars is severely suppressed by the presence of turbulence and only picks up once the mass of the clouds has increased to allow catastrophic collapse forming super-massive stars several ten thousand times the mass of the sun. The lifetime of super-massive stars is around a million years, after which they will collapse to form a black hole of similar mass, the seed of super-massive black holes that we see today.
Professor Khochfar commented:
This simulation is pointing the way to finally settle the 20-year-old question on the birth of super-massive black holes in the Universe. The beauty of the proposed black hole seeding channel is that it does not require any fine tuning and is a natural consequence of structure formation along the cosmic web in a Universe that consists of dark energy and dark matter.
The School welcomes applications from both external and internal scientists interested in applying for personal fellowships. We have an internal deadline on 18 July 2022 for STFC Ernest Rutherford, Royal Society University Research and EPSRC Postdoctoral and Open Fellowships.
We are keen to attract outstanding researchers from Edinburgh and across the world to join us as Postdoctoral Fellows. We offer a high quality research environment and support for you in your fellowship application process.
Fellowship opportunities
The School operates an internal review process for the following fellowship opportunities which have a deadline of noon, Monday 18 July 2022:
- STFC Ernest Rutherford Fellowships
- Royal Society University Research Fellowships
- EPSRC Postdoctoral and Open Fellowships
We also welcome applicants for other fellowships, the full list of which can be found on the weblink below.
Application information
Candidates are expected to have a PhD in Physics, Astronomy or a related discipline, and in most cases a few years research experience, as well as the ability to present clear evidence of their potential to undertake leading research.
The School of Physics and Astronomy is committed to advancing equality and diversity, welcoming applications from everyone irrespective of gender, ethnic group or nationality.
How to apply
Candidates must submit a research statement, CV and list of publications. Full application information can be found on the weblink below.
Congratulations to Dr William Barter who has been awarded a UK Research and Innovation (UKRI) Future Leaders Fellowship, and will be joining the School of Physics and Astronomy’s Particle Physics Experiment Group.
Fellowship scheme
The UKRI Future Leaders Fellowships have been instigated to ensure the strong supply of talented individuals needed for a vibrant environment for research and innovation in the UK.
In this round, 84 pioneering researchers, tech entrepreneurs, business leaders and innovators across different sectors and disciplines in Scotland will benefit from a £98 million cash boost to convert their innovative ideas to transformational products and services.
On the discovery of new particles
William is a particle physicist, leading research and research teams at the Large Hadron Collider, with over a decade of experience studying the weak force (which is responsible for radioactivity) and differences between matter and anti-matter. With the award of the Future Leaders Fellowship, William seeks the discovery of new fundamental particles. In our best theory of particle interactions at a quantum level, electrons are expected to behave in the same way as their heavier counterparts, the muon and the tau-lepton. However, recent measurements suggest that muons and electrons behave differently. Attempts to explain these results invoke new, currently unknown, fundamental particles, and also suggest that clear signs of this 'new physics' will be visible in analogous measurements of tau-leptons. William will develop novel techniques to detect these tau-leptons, and will use these techniques to search for definitive evidence of new particles. Such a discovery would herald a paradigm shift in our understanding of the universe.
Congratulations to Professor Wilson Poon whose contributions to the field of rheology have been recognised by the Eugene C. Bingham Medal.
Eugene C. Bingham Medal
The Eugene C.Bingham Medal is the highest award of the Society of Rheology and is given annually to an individual who has made outstanding contributions to the field of rheology.
The citation of Professor Poon’s award reads: “By combining rheological and microstructural measurements on carefully characterized model systems, Wilson Poon has transformed our understanding of the flow of colloidal gels, attractive and repulsive colloidal glasses, and non-Brownian suspensions of frictional particles. He has thereby elucidated universal principles underpinning the formulation of many industrial products.”
The Award will be presented at the 93rd Society of Rheology Annual Meeting to be held in Chicago, Illinois in October 2022, and will be accompanied by a plenary lecture by Professor Poon.
Soft Matter and Rheology
Based in the School’s Institute for Condensed Matter and Complex Systems, Professor Poon has spent many years working on 'model' colloids to study phenomena that are ubiquitous across condensed matter and statistical physics, particularly the structure and dynamics of arrested states such as glasses and gels. Understanding such states and how they flow – the science of ‘rheology’, is one of the grand challenges facing 21st century physics; precisely because of their interesting flow properties, such states occur widely in a very large range of industrial processes and products.
To exploit the latter connections, Professor Poon set up the Edinburgh Complex Fluids Partnership (ECFP) in 2012 to coordinate knowledge exchange with industry. ECFP clients now span many sectors, from food and confectionaries through personal care to specialty and agri-chemicals. He stresses that this is a genuine process of bidirectional knowledge exchange, and not a unidirectional ‘knowledge transfer’ from academia to industry as is often portrayed in discussions of such partnerships. Thus, some of his most impactful recent contributions, such as the work on the rheology of non-Brownian suspension mentioned in the Bingham citation, has arisen from real-life industrial problems and partly performed with industrial partners such as Mars Chocolate and Johnson Matthey.
Professor Poon’s other research interest includes suspensions of ‘active particles’ in the form of swimming bacteria. He has recently started investigating the ‘physics of death’ – how the phenomenon we call ‘life’ relies ineluctably on highly-organised processes of ‘self disassembly’ that feed back into equally highly-organised processes of ‘self assembly’. He also teaches and researches theology, the latter word being, amusingly, often a typo for the word ‘rheology’. Professor Poon is therefore looking forward to the almost inevitable announcement some day that he has been awarded the Bingham Medal for Theology!
A new European Space Agency science mission, proposed by the UK, to 3D-map a comet for the first time has reached a major milestone, moving from the design phase to implementation.
Comet Interceptor mission
The Comet Interceptor mission, which will further our understanding of the evolution of comets and will help solve some of the mysteries of the Universe, has been formally adopted by the European Space Agency (ESA).
Due for launch in 2029, the mission will see one main spacecraft and two robotic probes travel to an as-yet unidentified comet and map it in three dimensions.
The mission was first proposed by an international team led by University College London’s Mullard Space Science Laboratory (MSSL) in Surrey and the University of Edinburgh.
Professor Colin Snodgrass, who is based at the University of Edinburgh’s Institute for Astronomy, was deputy lead on the proposal, and leads the target selection team that is working to identify suitable comets, commented:
It is very exciting to be part of a mission that follows a completely new approach: designing and building the spacecraft before the target is even discovered. This opens up opportunities to visit space objects that were completely inaccessible before, such as comets entering the inner solar system for the very first time, or possibly even interstellar objects that formed around a distant star.
The UK Space Agency has so far provided £2.3 million in funding for two instruments on the mission: The Modular InfraRed Molecules and Ices Sensor (MIRMIS) instrument is led by the University of Oxford. MIRMIS will deliver a unique dataset, providing information such as the comet’s shape, size and rotation state. The Fluxgate Magnetometer (FGM) sensor led by Imperial College London and located on the ESA probe will provide high accuracy and high-time resolution measurements of the comet’s magnetic field strength and direction. One of the two robotic probes will be built by the Japanese Space Agency, with the team working to find a contractor for the main spacecraft and the other robotic probe.
Understanding the origins of our Solar System
Comets are what is left over when a planetary system forms and in each ancient object is preserved information about the formation of the Solar System 4.6 billion years ago.
Comet Interceptor would be the first mission to travel to a comet which has never previously encountered the inner Solar System.
To do this, it will need to launch and reach a holding position around 1 million miles away from Earth. There it will lie in wait – possibly for years - until astronomers on the ground spot a suitable comet for it to intercept. The two probes will make closer passes of the comet’s nucleus and beam their data back to the main craft.
This new ambush tactic is the first of its kind. The fly-by of the three spacecraft, including the two probes, which measure less than a meter across, is likely to take just a few hours but could illuminate conditions that prevailed more than 4 billion years ago.
Previous missions have studied comets trapped in short-period orbits around the Sun, meaning they have been significantly altered by our star’s light and heat. Breaking from that mould, Comet Interceptor will target a pristine comet on its first approach to the Sun.
The scientists are likely to target a comet travelling from the Oort Cloud — a band of icy debris that lies about halfway between the Sun and the next nearest star.
This debris was formed during the conception of the Solar System but was rapidly ejected to its outermost edge. Unlike more familiar comets, their surface will not have been vaporised by the Sun’s energy — a process that leads to dust building up on a comet, obscuring its original state.
Once the probes reach a pristine comet, they will study and scrutinise the chemical composition of it, with one aim being to evaluate whether similar objects may have brought water to planet Earth in the past.
Image gallery
The European Space Agency has released a new tranche of processed data from the Gaia space observatory – the result of several years’ work by hundreds of scientists, including a team at the Institute for Astronomy.
220 million spectra
On June 13th 2022 the European Space Agency releases a new tranche of processed data from the Gaia space observatory to the world scientific community. The release incorporates a rich variety of position, distance, spectroscopic and classification information for hundreds of thousands of solar system objects, 1.6 billion stars (including nearly ten million variable types and one million binaries), and millions of candidate galaxies and distant quasars. The spectroscopy alone amounts to some 220 million individual spectra, by far the largest haul of such data ever assembled. The data release is the result of several years’ work by hundreds of European scientists including a team at the Institute for Astronomy, based in the School of Physics and Astronomy.
Collaboration
The European Space Agency's Gaia space observatory has been scanning the entire sky since mid-2014, making position and brightness measurements as objects transit its focal plane.
Many hundreds of individual measurements for each of several billion objects have been amassed over the last seven years, and the satellite is still going strong with a projected life time now estimated at 10 years in total. Raw data from the giga-pixel cameras on-board is transmitted continuously to the ground where a network of data processing centres calibrate and prepare the data for science exploitation by the world astronomical community.
Edinburgh scientists and technical experts in the Institute for Astronomy are involved in this endeavour which is staffed by several hundred scientists, engineers and operations personnel spread around Europe. The UK part of the collaboration involves the universities of Edinburgh, Cambridge, Leicester, Bristol and University College London. Here in Edinburgh responsibilities include instrumental calibrations and core processing software for the imaging systems at the head of the data flow, and also preparing the final science-ready data products and delivery systems at the tails of the pipelines, all in collaboration with colleagues in the pan-European Gaia Data Processing and Analysis Consortium.
Precision
The Gaia telescopes and detection systems are highly complex and the data streams require much detailed treatment to extract the best possible measurements. Many repeat cycles of pipeline processing involving iteratively refined software must be undertaken in order to reach the ultimate precision which, in terms of position alone, is equivalent to resolving 3 cm sized features at the distance of the Moon (e.g. the width of a Lunar astronaut's gloved finger seen from Earth!).
Data release 3
Periodic data releases started in September 2016 and occurred at two-yearly intervals thereafter, each presenting increasing amounts of data and increasingly advanced data products. The latest, Data Release 3, occurs on June 13th this year and amounts to some 10 terabytes of products from measurements taken in the first three years of the mission. This latest release is a major milestone in that, for the first time, calibrated spectra for a significant fraction of the entire billion-source catalogue are provided, in addition to detailed astrophysical parameters for nearly half a billion sources enabling categorisation of their stellar types (luminosities, radii, etc). Nearly 34 million stars are provided with line-of-sight velocities from Doppler shift measurements of the lines in their high-resolution spectra, the largest radial velocity survey ever created. In conjunction with the positions, distances and angular movement of those stars this yields a full "six-dimensional" view of their locations and space velocities within the Milky Way. The release includes detailed data for around one million multiple star systems where two or more stars are in close orbits around each other. This supersedes all work on such systems undertaken in astronomy in the centuries since the invention of the telescope. These are just a few examples from the treasury of Gaia Data Release 3 - further details of the release are given in the links below.
Dr. Nick Rowell, Institute for Astronomy, School of Physics and Astronomy said:
The Gaia space telescope scans the sky 24 hours a day, measuring and cataloging every object bright enough to be detected by its sensors. This ranges from asteroids in the Solar System, through nearby stars, all the way to quasars in the distant universe.
Dr. Nigel Hambly, Institute for Astronomy, School of Physics and Astronomy, said:
Gaia is the mission that keeps on giving. Data releases up to now have yielded on average four to five research papers per day in international journals of research in astronomy and astrophysics. This is a figure that even surpasses that for the NASA/ESA Hubble Space Telescope. The mission is literally re-writing astronomy text books, but we're nowhere near the end yet. The latest release of data comprises merely 30% of the measurements in the projected final mission catalogue, yet it is nonetheless a huge leap forward in astronomical survey science.
Polymeric additives enable homogeneous drying of dispersed particles.
Have you ever spilled your coffee? You may have noticed how the coffee dries into an intriguing stain with a bright centre and a dark ring encircling it.
This ‘coffee ring’ forms because the liquid evaporates faster at the edges, inducing a flow from the droplet interior towards the outside. Suspended solid coffee particles thus accumulate at the drop edge, causing the characteristic ring pattern.
Inks and any other liquids containing solid materials behave like coffee – particles accumulate around the edges upon drying. The resulting uneven particle distribution presents a major challenge in ink-jet printed electronic devices, as it can lead to failure and a loss of performance.
In their Nature Communications paper, a team of researchers from the University of Edinburgh and the Friedrich-Alexander-University Erlangen-Nuremberg present a simple, yet versatile strategy to overcome the omnipresent coffee ring effect and achieve homogeneous drying patterns of particle dispersions. The strategy the researchers apply is to modify dispersed particles with polymeric additives. This induces additional steric repulsion, which prevents particle accumulation at the droplet edge and promotes adsorption to the droplet surface, resulting in a homogeneous particle film upon drying.
Importantly, the presented method is independent of particle shape and is applicable to a variety of commercial pigment particles and different dispersion media. The simplicity and versatility of the method paves the way towards reliable coatings and ink-jet printed electronic devices in a wide range of advanced technologies.
Congratulations to Prof Jorge Peñarrubia who has become a member of the Spanish Royal Academy of Sciences.
Royal Academy of Sciences of Spain
The Real Academia de Ciencias Exactas, Físicas y Naturales de España (Royal Academy of Sciences of Spain), has made dark matter researcher Professor Jorge Peñarrubia a member.
The Spanish organisation dates back to 1847, and was created to ‘promote the study and research of the exact sciences, physical, chemical, geological and biological, and their applications, as well as to spread this knowledge’. Membership includes around 400 ‘academicos’, 88 of whom are based outside Spain, with several Nobel laureates among them. Historic members include Michael Faraday, Alexander von Humboldt, Lord Rayleigh, Albert Einstein, Arnold Sommmerfeld, Hendrik Lorentz, Ernest Rutherford, Erwin Schroedinger, Werber Heisenberg, to name a few.
The nature of dark matter
Professor Peñarrubia’s research focuses on the nature of dark matter. Scientists have mounting evidence that dark matter is the main component of the Universe, yet do not know what it is. Professor Peñarrubia investigates how visible objects, like stars, move in the gravitational field generated by dark matter particles. To do so, he uses statistical-dynamical models, which he then compares against observations of the Milky Way, our home galaxy.
Reflecting on this recognition, Professor Peñarrubia said:
Becoming a member of the Royal Academy of Sciences represents a great honour in many ways. At a personal level, it feels very rewarding to receive such an important recognition from the country where I was born. At a professional level, it is an opportunity to strengthen the scientific ties between the United Kingdom, Scotland in particular, and Spain. This task has become crucial after Brexit, which threatens long-existing, successful collaborations between the two countries - and worse - thwarts future ones.
We are delighted to announce that the University of Edinburgh has been rated as one of the top centres for Physics & Astronomy research in the UK.
Overall results
The School of Physics & Astronomy at the University of Edinburgh was ranked 4th in the UK and 1st in Scotland in the Research Excellence Framework (REF) 2021 listing for the quality, scale and breadth of its research by Times Higher Education. This is particularly impressive as the School submitted 119 staff for assessment (an increase of 78% from REF2014).
97% of the School’s research outputs were measured as world-leading/internationally excellent (with a score of 4*/3*) and nearly half (46%) of the research outputs were judged to be world-leading (4*).
| Research Power Ranking* |
Institution |
| 1 | University of Oxford |
| 2 | University of Cambridge |
| 3 | Imperial College London |
| 4 | University of Edinburgh |
| 5 | University College London |
+ 39 other higher education institutions
* the Times Higher Education Research Power index values the influence of research by multiplying quality grading by the number of academic staff reported.
Within the top 5 physics departments in the UK, the School of Physics and Astronomy at the University of Edinburgh was ranked 3rd on quality of research.
These results confirm the exceptional performance of our staff, our excellent facilities, and our world-leading research.
Research excellence
The Research Excellence Framework (REF) is the UK’s system for assessing the quality of research in UK higher education institutions. Universities are evaluated on the standard of their research, the environment in which it is conducted, and the positive impact it has on the world.
Building on the results of the previous REF in 2014, the School of Physics & Astronomy has been rated even more highly in this latest REF2021 assessment exercise.
Our success is a ringing endorsement of our ability to expand our research base, while at the same time enhancing quality, by attracting and hiring many of the very best researchers from around the world.
Impact and breadth
Our impact ranges from the design of base stations on Mars, through the use of materials research to inform more sustainable food production, to the design of the next generation of computers.
We look forward to continued growth and the exciting research ahead in fields as diverse as cosmology, condensed matter, extrasolar planets, elementary particles and nuclei, and the physics of life.
Space urgently needs special legal protection similar to that given to land, sea and atmosphere to protect its fragile environment.
An influx of space debris in orbital space – around 100 kilometers above the earth’s surface – caused by the rapid growth of so-called satellite mega-constellations is endangering this precious ecosystem, researchers say.
The installation of these huge clusters of hardware, some with up to tens of thousands of satellites delivering broadband to Earth, are congesting space and rocket launches are also polluting the atmosphere. Pieces of broken satellites, which travel at enormous speeds through orbital space threaten working satellites in their path, the paper says. Furthermore, streaks from satellite flares, which cause light pollution, are increasingly disrupting research. The giant Vera C. Rubin Observatory in Chile, which aims to carry out a 10-year Legacy Survey of Space and Time, will be badly affected, for example.
The paper, published in Nature Astronomy, argues that space is an important environment for all professional astronomers, amateur stargazers and indigenous peoples and the scientific, economic and cultural benefits of space should be carefully considered against these damaging environmental impacts. Addressing these issues requires a holistic approach that treats orbital space as part of the environment and worthy of environmental protection, at national and international levels, experts say. The researchers urge policy-makers to consider the environmental impacts of all aspects of satellite constellations – including their launch, operation and de-orbit – and to work collaboratively to create a shared, ethical, sustainable approach to space.
The research, led by the University of Edinburgh, is connected to a legal case currently before the US Court of Appeal, which will set an important precedent in the growing campaign for space environmentalism.
Professor Andy Lawrence, Regius Professor of Astronomy, University of Edinburgh Institute for Astronomy and lead author, said:
We are standing on a watershed in history. We can cheaply launch huge numbers of satellites and use them to the benefit of life on Earth – but this comes at a cost. As well as damaging stargazing, the space industry may be shooting itself in the foot.
Professor Lawrence brought these issues to popular attention in his book, Losing The Sky. The publication led to him writing an expert witness statement for a legal case currently before the US Court of Appeal which argued that US environmental regulations should apply to space launch licensing.
Professor Moriba Jah, co-author and Associate Professor of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin, said:
We believe that all things are interconnected and that we must embrace stewardship as if our lives depended on it. Traditional ecological knowledge holds a key to solving this wicked problem. The largest challenge we have is in recruiting empathy and compassion toward solving these environmental crises. If we can find innovative ways to enable the general public to project themselves into this dire condition, and feel concern to address it, the earth, and all of the lives she sustains, wins.
Professor Jah recently co-founded the start-up, Privateer Space together with Apple co-founder Steve Wozniak and CEO of Ripcord, Alex Fielding. The company takes a novel approach to mapping the objects in orbit accurately, in near real-time, to enable the sustainable use of space by a growing number of operators.
Dr Meredith Rawls, co-author and researcher at the University of Washington, said:
Rubin Observatory will be one of the most severely impacted astronomy facilities by large numbers of bright satellites due to its large mirror and wide field of view — the same characteristics that make it such a remarkable engine for discovery. I care a lot about how satellite streaks affect science, but the case for dark and quiet skies is much larger than that. We need all hands on deck to address the rapidly changing satellite situation if we can hope to co-create a future with dark and quiet skies for everyone.
Dr Rawls is a leading actor in the new International Astronomical Union (IAU) Centre for the Protection of the Dark and Quiet Skies from Satellite Constellation Interference which aims to bring together sky observer stakeholders to collaborate on quantifying, mitigating and disseminating the impacts of satellites.