Short term visitors programme, Newcastle University

Lead Research Organisation: Newcastle University
Department Name: Mathematics and Statistics

Abstract

Maps of the sky made at wavelengths longer than visible light are covered in random patterns. These patterns are imprinted on the observed radiation by events that occurred very early in the Universe's history and by the structure of our own Milky Way galaxy. So the mathematical properties of the maps can tell us a lot about the evolution of the Universe and our local neighbourhood: but first we have to separate the foreground of the Milky Way from the cosmic background. The randomness in the Milky Way emission arises from turbulence in the interstellar gas and associated tangling of the magnetic fields which pervade the space between stars. Cosmic rays (electrons travelling at close to the speed of light) spiral around the magnetic field lines and produce radio waves that are detected by satellite and ground based telescopes: in order to understand the data we need to relate the two-dimensional observations to the three-dimensional properties of the region from which they come. Part of our research plan is to develop new methods of analysing the observed maps in order to learn about the gas, magnetic field and cosmic rays in our Galaxy, particularly how these components fit together, and what we can learn about the ubiquitous turbulence that is characteristic of most astrophysical flows. From the cosmological perspective, the random patterns can be used to study the theory of inflation: the process that caused the Universe to rapidly expand shortly after the big bang. Two satellites, WMAP and the forthcoming PLANCK mission, provide data that will open a new window on the story of how our Universe evolved and on some of the most interesting problems of fundamental physics. We will be comparing the new observations with the predictions of different theoretical models of inflation. The astrophysical and cosmological aspects of our research are closely linked and we will be inviting international experts, both astronomers and theorists, to Newcastle to help us to make progress. Magnetic fields are present in nearly all astronomical objects, from stars and planets to the furthest reaches of intergalactic space. As well as the turbulent, tangled magnetic field already mentioned interstellar magnetic fields have a component that is arranged in enormous spiral patterns, on scales comparable to a whole galaxy. Our work leads us to ask where these fields come from and how they came to be organised on such large scales: the theory of astrophysical dynamos provides the most promising explanation. As part of this research project we will be developing models of galactic dynamo action, identifying signatures of a dynamo at work that can be observed and comparing the results with maps obtained by radio astronomers.

Publications

10 25 50
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Baggaley A (2010) Fluctuation dynamo based on magnetic reconnections in Astronomische Nachrichten

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Berkhuijsen E (2012) Density PDFs of diffuse gas in the Milky Way in EAS Publications Series

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Berkhuijsen E (2008) Density probability distribution functions of diffuse gas in the Milky Way in Monthly Notices of the Royal Astronomical Society: Letters

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Favier B (2011) Small-scale dynamo action in rotating compressible convection in Journal of Fluid Mechanics

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Fletcher A (2011) Magnetic fields and spiral arms in the galaxy M51 Magnetic fields and spiral arms in M51 in Monthly Notices of the Royal Astronomical Society

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Fletcher, A (2010) Magnetic Fields in Nearby Galaxies in The Dynamic Interstellar Medium: A Celebration of the Canadian Galactic Plane Survey.

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Gent F (2013) The supernova-regulated ISM - I. The multiphase structure in Monthly Notices of the Royal Astronomical Society

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Gent F (2013) The supernova-regulated ISM - II. The mean magnetic field in Monthly Notices of the Royal Astronomical Society: Letters

 
Description Results have been used in public lectures and outreach events.
First Year Of Impact 2009
Sector Other
Impact Types Cultural

 
Description Leverhulme Trust Research Grant
Amount £134,000 (GBP)
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 05/2011 
End 04/2014
 
Description Royal Society International Project
Amount £12,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2011 
End 02/2013
 
Description Joint work with Russian colleagues 
Organisation Russian Academy of Sciences
Department Institute of Continuous Media Mechanics
Country Russian Federation 
Sector Academic/University 
PI Contribution Expertise in analysis of radio astronomy data, dynamo theory, advanced mathematical methods for modelling and image analysis.
Collaborator Contribution Jointly work on research problems.
Impact Received grant for International Project from the Royal Society. Several papers in preparation.
Start Year 2011