Fresh insight into how stars are formed is challenging scientists’ understanding of the Universe. A study of intense starbursts – events in distant galaxies in which stars are generated hundreds or thousands of times faster than in our Milky Way – is changing researchers’ ideas about cosmic history.
The findings will help scientists understand how galaxies in the early Universe evolve into those we see today. Instead of observing the optical light from starbursts, which is obscured by enormous quantities of dust, scientists instead observed radio waves, measuring the relative abundances of different types of carbon monoxide gas. They were able to differentiate between the gas expelled from massive stars, which shine very brilliantly for a short time, and that expelled from less massive stars, like our own Sun, which can shine steadily for billions of years. Applying this novel technique for the first time, astronomers found that stars born inside galaxies undergoing a powerful starburst tend to be massive. In this regard, these are very different from those born inside galaxies that build up their stars over billions of years.
Scientists verified their findings using powerful computer models based on the evolution of our Milky Way galaxy and by observing starburst galaxies in the early Universe, which formed within a few billion years of the Big Bang. Such young galaxies are unlikely to have undergone previous episodes of star formation, which might otherwise have confused the results.
Researchers collected their data using the powerful ALMA telescope in the high Atacama Desert in Chile.
The five-year study, published in Nature, was carried out by astronomers at the University of Edinburgh and the European Southern Observatory (ESO), working alongside experts in Italy and Greece. It was supported by the European Research Council. The ALMA telescope is operated by a partnership of the ESO, the US National Science Foundation and the National Institutes of Natural Sciences of Japan, in cooperation with the Republic of Chile.
Dr Zhi-Yu Zhang, of the University of Edinburgh’s School of Physics and Astronomy, who led the study, said: “Traditional telescopes are of limited use when studying dusty starburst galaxies. We reached our results using a powerful new radio telescope, hunting for traces of chemical elements from past events. For astronomers, these are like fossils. The results challenge classical ideas about the formation of stars in galaxies across cosmic time.”
Professor Rob Ivison, of the University of Edinburgh’s School of Physics and Astronomy and ESO, said: “Our findings lead us to question our understanding of cosmic history. Astronomers building models of the Universe must now go back to the drawing board, with yet more sophistication required.”
The Higgs Centre for Innovation, which supports start-ups and SMEs working in the space and data-intensive sectors, has officially opened at the Royal Observatory Edinburgh.
Entrepreneurial boost
The centre links to industry with cutting-edge scientific and engineering expertise. It focuses on supporting business both through incubation activities and access to facilities, including laboratories and working space, for small and medium-sized enterprises (SMEs). Connecting engineers, academics and PhD students directly with small businesses will help boost their entrepreneurial experience at the start of their research careers.
The stand-alone building at the Royal Observatory Edinburgh is run by the Science and Technology Facilities Council in partnership with the University.
£11 million investment
The Centre aims to create new market opportunities, especially in big data and space technologies. It is funded through a £10.7 million investment from the UK Government. The Science and Technology Facilities Council will invest £2million over five years to operate the centre.
Prof James Dunlop, Head of the Institute for Astronomy, University of Edinburgh reported:
The construction of the Higgs Centre for Innovation is an exciting new development in the long established collaboration between STFC and the University of Edinburgh at the Royal Observatory Edinburgh. The new centre will cement Edinburgh's reputation as a world leader in the fields of astrophysics and big data, and provide new opportunities for knowledge exchange between astronomers, particle physicists, engineers and industry.
Gillian Wright, Director of the UK Astronomy Technology Centre commented:
A huge amount of work has been put in by all partners over the past few years to develop plans for the Higgs Centre for Innovation. We look forward to developing new partnerships at the centre and seeing the benefits it will bring to future generations of scientists and industry.
The Higgs Centre for Innovation is named in honour of Professor Peter Higgs of the University’s School of Physics and Astronomy. The pioneering scientist received a Nobel Prize in Physics in 2013 for his prediction of the existence of the Higgs boson particle, which enables other particles to acquire mass. This fundamental particle was discovered by scientists at the European Organization for Nuclear Research (CERN) in 2012.
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Congratulations to Dr Jamie Cole and Prof Philip Clark for their success in the 2018 Teaching Awards.
Jamie won the award for Best Personal Tutor. This is the second time Jamie has won this award, the first being in 2016. This demonstrates his continued effort in student support.
Philip achieved the runner-up award for Best Implementer of Student Feedback.
Dr Jamie Cole commented:
Personal Tutors in the School of Physics & Astronomy are dedicated to helping students realise their academic potential. The recognition I received – which belongs also to many equally deserving colleagues and to our excellent Student Support Team – will encourage the School in its desire to provide a high level of support to our students within a vibrant, challenging and hopefully rewarding learning environment.
Prof Arthur Trew, Head of School reported:
We are incredibly pleased by this result, which demonstrates our students’ recognition of the pastoral care that we give them and our efforts in implementing course changes following feedback from students. Over the past few years we have had more than our fair share of EUSA Teaching Awards, but winning both an award and runner up place, and with a second win for Dr Cole, this is great news for us. My congratulations to both Dr Cole and Professor Clark.
EUSA Teaching Awards
The EUSA Teaching Awards celebrate the best contributions made to students’ learning experiences. This year, there were over 1,600 nominations for courses, teaching staff, dissertation supervisors, professional and administrative staff.
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Understanding how bacteria stick, the differences of adhesion within a population of bacteria, and its influence in biomedical applications.
Bacteria are very good at sticking to surfaces, where they can be a major source of infections. For example, they can contaminate medical devices, food packaging and drinking water systems, and there are ongoing efforts to design surfaces that prevent bacterial adhesion. A team of researchers from the School of Physics and Astronomy and School of Engineering used cutting-edge microscopy and image analysis techniques to probe the adhesion of rod-shaped Escherichia coli bacteria to glass surfaces. It appears that there are large differences between individual bacteria in how they stick to the surface that can be explained with a “patchy model”.
The researchers recorded movies of many bacterial cells on a glass surface. Using in-house developed software, they followed the positions and orientations of the cells and studied their dynamics. Some bacteria readily adhere to the surface while others never do. Even if they adhere, there can be differences between individual cells. Some cells attach to a surface for several hours, while others bind only weakly and detach rapidly.
The results can be explained with a model in which bacteria adhere with a limited number of adhesive patches on their body. Strong adherers can stick with multiple patches, while weakly adhering cells are bound with just a single patch, and non-adhering cells have no adhesive patches at all. Interestingly, all these differences are found within populations in which all cells should have the same genes. Apparently, individual cells express these genes differently, thus making the behaviour of each cell differ.
Apart from the academic relevance, the results of the study can be used to realise novel anti-adhesion surfaces. It seems the design of such materials should take into account that not all cells stick in the same way, and that adhesion takes place on specific spots on the bacteria.
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The second release of results from the European Space Agency's Gaia mission takes place to the world scientific community. Gaia Data Release 2 (GDR2) marks an enormous step forwards for astronomy, providing a map of the Milky Way galaxy in orders of magnitude larger and more precise than that available previously.
Gaia has been in routine operations for nearly four years. This ambitious space astronomy project aims to map a substantial part of our galaxy over a mission lifetime of more than 5 years, eventually scanning the entire sky around 70 times.
The spacecraft orbits the Earth at a distance of 1.5 million kilometers in the Lagrange-2 region, 4 times further away than the Moon. This is a quasi-stable point in the Sun-Earth system with an orbital period of one year, in the opposite direction to the Sun as seen from Earth.
Gaia scans continuously with a rotational period of 6 hours, building up a map of the sky with exquisite angular resolution, unhampered by the blurring effects of the Earth's atmosphere. GDR2 contains the positions, distances, optical brightness and colours of more than one billion stars. Supplementary information in the form of spectroscopic radial velocities, variability light curves and stellar astrophysical parameters are also available for subsets of the main catalogue. This release of data marks a major leap forward in our knowledge of the Galaxy with 500x more stellar distances measured than in the first data release in September 2016. That previous release was in itself a significant step forward, with 20x more stellar distances measured than by the precursor Hipparcos mission in the early 1990s.
A small team of scientists and developers based in the Wide Field Astronomy Unit of the Institute for Astronomy (IfA) in the School of Physics and Astronomy have been working on the project for more than ten years. The team currently comprises Michael Davidson, Nigel Hambly and Nick Rowell. The team is responsible for several key calibration subsystems within the on-ground data processing pipelines that have been developed for Gaia by a collaboration of hundreds of engineers and scientists spread around Europe. Further details of the IfA's involvement can be found in a previous School News item coinciding with the launch of Gaia back in December 2013.
Dr. Hambly reported "This is a significant milestone for the Gaia project and demonstrates the superb quality of the data gathered so far. The information content of GDR2 is a huge step forward and we are continuing to work on improvements for later data releases."
Dr. Davidson said "The launch of Gaia brought many surprises and challenges as we came to know the spacecraft. Now each data release is eagerly anticipated by the astronomy community."
Dr. Rowell commented "The Gaia catalogue represents an enormous and rich dataset that will be exploited by astronomy researchers for decades to come."
GDR2 represents only an intermediate step in the science exploitation of Gaia data, being based on 22 months of observations. The European teams within the Gaia Data Processing and Analysis Consortium are already working on the next data release with improved software and calibrations. GDR3 will take place towards the end of 2020, and will contain the analysis of around 36 months of data. The calibration improvements coupled with more measurements taken over a longer time will lead to even greater precision in the 3D positions and space motions contained within the multi-billion row Gaia star catalogue.
The Wide Field Astronomy Unit's participation in the European Space Agency Gaia Data Processing and Analysis Consortium is funded by grants from the UK Space Agency and Science and Technology Facilities Council.
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Edinburgh Complex Fluids Partnership (ECFP) and the School of Physics and Astronomy swapped lab coats for wizard robes at the Edinburgh International Science Festival to present ‘Physics Wizardry: Potion and Alchemy Class’.
Classes took place at the National Museum of Scotland and the children/apprentice physics wizards were introduced to the magic world of potions by Headmaster Dr JC Denis who kicked off the class by demonstrating ferromagnetic and photochromic liquids. The kids were then sorted into four houses where they undertook potion classes and demonstrations.
Potions classes
In the baby-boggarts class, wizards were taught how to make slime and how these materials have both solid and liquid like properties similar to shapeshifters in the magical world. The divination activity demonstrated how liquids with different surface tensions spread when mixed, creating beautiful patterns - a bit like reading tea leaves. When brewing polyjuice potion, wizards learned how to make the base of many magical potions/complex fluids: mixing liquids which normally do not like to mix, and stabilising these mixes.
Industry demonstrations on polymer solutions
Colleagues were joined by local industrial partner, Hyaltech, who took apart a large model of the eye and described why special polymer solutions are required to maintain space while the lens is exchanged for a new one during cataract surgery. The children then created multi-coloured hydrogel beads to take home, by squirting coloured polymer solutions into a salt solution (which induces cross-linking between polymer chains).
Capturing memories in the pensive
After the workshops, wizards then reviewed what they had learned and wrote their best memories of the workshop on magical pensieves (turntables filled with rheoscopic fluid).
Wizarding community
Around 210 apprentice physics wizards attended these events as part of the Edinburgh International Science Festival. The event was coordinated by the Ogden-ECFP Outreach Officer, Dr JC Denis, with input from PhD students and academic staff.
The annual Institute of Physics conference in high energy and astroparticle physics features a fiercely fought poster prize. This year’s winner is Elizabeth Leason, a PhD student from the School of Physics and Astronomy’s Particle Physics Experiment group.
Elizabeth is conducting research within the dark matter team. Dark matter is the mysterious invisible substance known to make up around 85% of the mass of our Galaxy. Its fundamental particle nature remains unknown. One possibility is that there is a dark partner for every standard model particle that we know of, with many of the same characteristics and properties. Such particles would form ‘mirror’ nuclei and atoms – indeed, a mirror universe. Using data from the Large Underground Xenon (LUX) experiment, a major international project situated a mile underground in South Dakota, USA, Elizabeth has now set the first direct experimental constraints on the mirror dark matter model, ruling out much of the allowed parameter space.
The poster prize is especially remarkable for two reasons: Elizabeth is still in the first year of her PhD, and last year’s winner was also from the dark matter team here at the University of Edinburgh.
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The School of Physics and Astronomy is delighted to welcome Lucinda Bruce-Gardyne, Founder of Genius Foods Ltd as our Royal Society Entrepreneur in Residence.
For the next two years, Lucinda will spend one day a week helping physicists to think more broadly about the applications of their research, to encourage entrepreneurial thinking and improve links to those in business, particularly in the food industry. Lucinda will be based within the Edinburgh Complex Fluids Partnership.
Lucinda commented:
I am thrilled and honoured to be appointed Royal Society Entrepreneur in Residence for the School of Physics and Astronomy. I look forward to working with its staff, researchers and students to create a culture that embraces entrepreneurial activity and collaborations within the school, the University and industry.
Professor Arthur Trew, Head of the School of Physics and Astronomy reported:
I am extremely pleased to welcome Lucinda to the School. We already have a number of successful examples of Knowledge Exchange: Wide-Field Astronomy Unit and Lockheed Martin; PPT and Intel; and the Edinburgh Complex Fluids Partnership, but such projects will become even more important through funding initiatives such as the Industrial Strategy Challenge Fund. Over the next couple of months she will be talking to people around the School and at the Higgs Centre for Innovation.
Dark matter makes up most of the mass of the Universe, yet it remains elusive. Depending on its properties, it can be densely concentrated at the centres of galaxies, or more smoothly distributed over larger scales. Researchers realised that studying the behaviour of clusters of stars within a galaxy could enable them to derive details about dark matter.
The tightest constraints on dark matter come from the very smallest galaxies in the Universe, known as dwarf galaxies. The smallest of these contain just a few thousand or tens of thousands of stars – so-called ultra-faint dwarfs. Such tiny galaxies, found orbiting close to the Milky Way, are made up almost entirely of dark matter.
By comparing the distribution of dark matter in galaxies with detailed models, researchers can test ideas for what might constitute dark matter. If the distribution of dark matter in these galaxies could be mapped out, it could provide new information about its nature. However, being devoid of gas and containing very few stars, until recently there was no viable method for making this measurement. Researchers from the Universities of Edinburgh and Surrey developed a new method to calculate the inner dark matter density of dwarf galaxies - even those with no gas and very few stars.
The key to the method lies in gravitationally bound collections of stars within galaxies, known as star clusters, which orbit close to the centre of the dwarf. Unlike galaxies, star clusters are so dense that their stars gravitationally scatter from one another, causing them to slowly expand.
The research team realised that the rate of this expansion depends on the gravitational field in which the star cluster orbits and, therefore, on the distribution of dark matter in the host galaxy. The team used a large suite of computer simulations to show how the structure of star clusters is sensitive to whether dark matter is densely packed at the centre of galaxies, or smoothly distributed. Scientists then applied their method to the recently discovered ultra-faint dwarf galaxy, Eridanus II, finding much less dark matter in its centre than many theoretical models would have predicted.
Their study was published in Monthly Notices of the Royal Astronomical Society (MNRAS) and funded by the European Research Council.
Dr Jorge Peñarrubia, who took part in the study, said:
These findings lend a fascinating insight into the distribution of dark matter in the most dark matter-dominated galaxies in the Universe, and there is great potential for what this new method might uncover in the future.
School of Physics and Astronomy colleagues remember Professor Clive Greated who sadly passed away. Clive joined the School of Physics and Astronomy in 1972 as Senior Lecturer and was subsequently promoted to Reader, and then to the Chair of Fluid Dynamics in 1982. He retired in 2005, was appointed Professor Emeritus and Senior Honorary Professorial Fellow and continued to be actively involved in teaching, research and public engagement activities.
Previously he was Lecturer in the Mathematics Department at Southampton University, Whitworth Fellow at Emmanuel College Cambridge and engineer at the Danish Institute of Applied Hydraulics. He obtained his BSc, PhD and DSc degrees from London, Southampton and City universities respectively. He was elected Fellow of the Royal Society of Edinburgh in 1983.
Research contribution
Clive Greated was head of the Fluid Dynamics and Acoustics group which pioneered the development of laser measuring techniques for the study of wave motions in both fluids and gases. He was one of the first to apply Laser Doppler Anemometry and Particle Image Velocimetry to study water wave dynamics and acoustic fields. These techniques are now fundamental to a number of research programmes within the School of Physics and Astronomy as well as those in other Schools. His reputation in this field led to international lecture tours, numerous research collaborations and grants funded from government agencies and industry.
Publications
He published around 100 papers in leading journals such as Journal of Fluid Mechanics, Physical Review, Acta Acustica, Acustica, Proceedings IEEE, Journal of Physics as well as numerous papers in conference proceedings. He was co-author of three books; Laser Systems in Flow Measurement, the Musicians Guide to Acoustics, and Musical Instruments: History, Technology and Performance.
Public Engagement
He was extensively involved in promoting the University, and the public awareness of science, through workshops, exhibitions and broadcasts.
Teaching and student welfare
His contribution to teaching has spanned wide subject areas from Fluid Dynamics to Sound Synthesis. He has contributed to the introduction of new degrees combining Physics with Music, and acted as Personal Tutor and Supervisor for numerous students. He continued to teach on the MSc in Acoustics and Music Technology until a few months before his death.
Music
His semi-professional career as a musician dates back to the age of 14 when he started playing saxophone with big bands in the London area. After moving to Scotland he turned mainly to playing keyboards, accompanying cabaret artists in clubs in and around Edinburgh and Glasgow. Most recently he played the keyboard for Edinburgh-based band Obsession. Despite being unwell, Clive gave his last performance on Hogmany 2017. He holds Licentiate teaching diplomas in piano and flute from the Royal Academy of Music and Trinity Colleges of Music.
Family
Clive is survived by his wife, Yrsa, their two daughters Alicia and Marianne, and three grandchildren.
Reflections
Former student and colleague Dr Michael Newton reflects on the influence Clive had on his career:
From my perspective, I would say that my overriding memory of Clive is what a tremendous encouragement he was to me, especially in the early days of my academic career. Having such a well-respected colleague show belief in you is probably one of the most positive and motivating things a young researcher can experience. His longstanding belief in the value of truly interdisciplinary research and teaching, covering everything from low level fluid mechanics, to musical instruments, and human hearing, continues to reverberate in the existence of the ongoing cross-College collaboration that is the Acoustics and Audio Group. For this, many of us still working in the subject area today owe him debt of gratitude.
Alistair Arnott, who worked with Clive commented:
Clive was incredibly successful at building the Fluids Dynamic group. Dealing with many students and postdoctoral staff, he never turned anyone way saying he was too busy. Clive was an optimist, and he had a knack of making everyone feel welcome, and would put his faith in others.
He was involved in experimental techniques for measuring fluid flow and applying them to various projects using the application of physics to real problems such as coastal erosion, pneumatic transport & pollution dispersion. He was also very keen on demonstrating the Fluid Dynamic group's wave tanks and lasers to visiting school groups.
His enthusiasm was equally as strong when it came to music. It's said that mathematically-minded people are good at making music and Clive could back that up. It was as though he could charm a tune out of any instrument he picked up!