Horizon UK 2009

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics

Abstract

Galaxies sit at the crossroads between cosmology and star formation research. They start as tiny overdensities in an almost homogeneous Universe. These overdensities grow and collapse under the attractive pull of the gravitational force which fights against the accelerated expansion of the Universe. Initially, these overdensities are predominantly composed of what astrophysicists call dark matter. With time, gravity sculpts the dark matter into a web of filaments that gas flows along until it is pulled into the larger dark matter concentrations at the filament intersections. Once the gas becomes sufficiently dense, some of it is transformed into stars by processes that we know very little about. At this point, the invisible dark matter halos shine with the light of their stars and galaxies are born. The most massive among these stars eventually explode as supernovae releasing mass and energy into the surrounding gas. As time proceeds, the smaller galaxies merge to form larger objects. Given their hierarchical growth, galaxies are exquisitely living structures, strongly shaped by their environment. Meanwhile the complex small-scale physics which governs how much gas is funnelled into stars, and the role of processes, such as supernovae explosions, that dump energy back into the gas, is unbelievably obscure. The complexity of the physics involved, coupled to the tremendous range of scales and masses to cover has always stood as an impediment to our understanding. But with today's powerful CPU chips coupled with state of the art numerical techniques we are poised to try to move galaxy formation research to the next level of sophistication: one where we attempt to grasp what's happening on the small, star forming scales while still capturing the essential aspects of what is structuring galaxies on larger scales. This grant asks for funds to acquire a computer powerful enough to analyze monstrously big simulations of large volumes of the Universe evolved for the first billion years of its life. In addition, we plan to use such a computer for zooming in on individual galaxies and follow the details of a galaxy's growth to the point that we can begin to understand the metamorphosis of its gas into stars.

Publications

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Aumer Michael (2017) Migration and kinematics in growing disc galaxies with thin and thick discs in Monthly Notices of the Royal Astronomical Society

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Aumer Michael (2015) Origin of the high v los feature in the Galactic bar in Monthly Notices of the Royal Astronomical Society

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Aumer Michael (2015) Origin of the high v los feature in the Galactic bar in Monthly Notices of the Royal Astronomical Society

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Aumer Michael (2016) Age-velocity dispersion relations and heating histories in disc galaxies in Monthly Notices of the Royal Astronomical Society

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Aumer Michael (2016) The quiescent phase of galactic disc growth in Monthly Notices of the Royal Astronomical Society

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Aumer Michael (2017) The structural evolution of galaxies with both thin and thick discs in Monthly Notices of the Royal Astronomical Society

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Beckmann R. S. (2017) Cosmic evolution of stellar quenching by AGN feedback: clues from the Horizon-AGN simulation in Monthly Notices of the Royal Astronomical Society

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Bisbas T. G. (2015) STARBENCH: the D-type expansion of an H II region in Monthly Notices of the Royal Astronomical Society

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Chisari N. (2016) Redshift and luminosity evolution of the intrinsic alignments of galaxies in Horizon-AGN in Monthly Notices of the Royal Astronomical Society

 
Description We have hammered away at the puzzles concerning the formation and evolution of galaxies by
increasing both the resolution and physics (e.g. radiative transfer, magnetohydrodynamics)
in cosmological Adaptive Mesh Refinement
hydrodynamics simulations. Highlights of our work include driving galactic winds
powered by individual supernovae and tracing gas flows from the cosmic web to galaxy cluster scales down 7 orders of magnitude to within around 60 lightyears
around a supermassive black hole. On the technical side we have set the standard for how to model a dual mode of energy release from supermassive black holes in
galaxies. While pursuing more realistic modelling of winds and blast waves from stars and black holes in order to see how they push, heat and ionise their surroundings
in an ongoing fight against gravity, we have also put great effort into chasing the origin of the angular momentum in galaxies, closely examining the role played by the \
cosmic web. A powerful consequence of this work
has been our prediction of the extent to which the weak lensing signal set to probe the Universe's mysterious dark energy might be contaminated by the intrinsic
alignments of galaxies within the cosmic web.
Exploitation Route This research is ongoing. Advances in numerical techniques and computational power will allow us to model increasingly more complex physics at increasingly higher resolution.
Sectors Education

 
Description Simulation results have been using in public outreach.
First Year Of Impact 2011
Sector Education
Impact Types Societal

 
Description British Council Alliance Grant
Amount £5,000 (GBP)
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 12/2009 
End 12/2011
 
Description Franco-Korean Star grant
Amount £28,000 (GBP)
Organisation Hubert Curien Programme 
Sector Charity/Non Profit
Country France
Start 06/2009 
End 06/2011
 
Description Oxford Martin School
Amount £360,000 (GBP)
Organisation University of Oxford 
Department Oxford Martin School
Sector Academic/University
Country United Kingdom
Start 10/2010 
End 10/2013
 
Description Franco-Korean Star grant 
Organisation Yonsei University
Department Programme Hubert Curien
Country France 
Sector Academic/University 
PI Contribution We have held 4 workshops with our Korean partners, and are writing several papers with them on galaxy evolution, and clusters.
Impact We are in the process of writing papers with our partners
Start Year 2009
 
Description Oxford Martin School: Programme on Computational Cosmology 
Organisation University of Oxford
Department Oxford Martin School
Country United Kingdom 
Sector Academic/University 
PI Contribution We are interacting with other members of the Oxford Martin School through interdisciplinary seminars and workshops.
Impact We have appointed a James Martin fellow with some of this money which will arrive in October 2011.
Start Year 2010
 
Description Oxford-Lyon Alliance Grant 
Organisation Claude Bernard University Lyon 1 (UCBL)
Department Astrophysics Research Centre of Lyon (CRAL)
Country France 
Sector Academic/University 
PI Contribution We are working together to do Adaptive Mesh Refinement simulations of galaxies with ionizing radiative transfer, and also we are post-processing our simulations with Lyman-alpha radiative transfer to make predictions for future instruments. The Horizon-UK machine is instrumental to the collaboration, as we are are running the high resolution simulations on it. The project involves the training of several students on both the UK and french side.
Impact We have run the first high resolution resimulation of a galaxy in a cosmological context with ionizing radiative transfer and are analyzing it to understand the impact of the radiation on galactic winds, star formation and dwarf galaxy formation.
Start Year 2009
 
Description Book and audiobook 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Presents an accessible account of cosmology

Introduces the public to the mysteries of cosmology
Year(s) Of Engagement Activity 2009
 
Description Portraits Savants 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact To explain a scientist's passion for the questions we study and engage
young people into research.

Inspire people to do science
Year(s) Of Engagement Activity 2011
 
Description Rockets workshop 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Schools
Results and Impact 30 pupils attended a talk about rockets and space travel, then
participated in a workshop to make a working model rocket and discuss
the physics involved.

not known
Year(s) Of Engagement Activity 2010
 
Description School Visits 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? Yes
Primary Audience Schools
Results and Impact Both talks took place in schools in Lyon, France
1 session with 49 pupils (16-17 year old)
1 session with ~ 25 pupils (18 years old)
It was a research talk, with discussion about why I chose to become a scientist, and the importance of international collaboration.

Teachers wanted pointers to educational material.
Year(s) Of Engagement Activity 2011
 
Description Schools evening in the department 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Schools
Results and Impact Talk to ~20 sixth formers about the numerical simulations we do at Oxford, followed by questions as well as a chance to use the dept telescope and Galaxy Zoo (developed at Oxford). The pupils and teachers seemed enthused and asked a number of questions about the talk and about physics in general.

not known
Year(s) Of Engagement Activity 2011
 
Description Starmus festival 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Amateur and professional astronomers exchange ideas about the cosmos.

Inspire the public to think about the Universe
Year(s) Of Engagement Activity 2011
 
Description Talks to school pupils 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience Schools
Results and Impact 30 pupils attended a talk about cosmology and astrophysical
research, followed by questions

not known
Year(s) Of Engagement Activity 2010