The Evolution of Mass and Light

Lead Research Organisation: University of Nottingham
Department Name: Sch of Physics & Astronomy

Abstract

The fellowship programme is centred upon the Herschel Satellite's two largest imaging surveys. Using these, the programme will investigate two fundamental but poorly understood aspects of galaxy evolution. Herschel operates in an unexplored region of the electromagnetic spectrum (0.1-0.5 mm) where an incredible 50% of the Universe's radiation is emitted. The sources that dominate at these wavelengths are young dust enshrouded star forming galaxies that typically evade detection in the optical. A tantalisingly small fraction of these galaxies have been seen at other wavelengths from the ground comprising only a very bright distant subset. These rare galaxies are merely the tip of the iceberg, not representative of the whole population. Frustratingly, little is known about the evolution of these distant systems and their relationship with local galaxies because the underlying population bridging the huge void has not been detected. This is a vital missing piece of the galaxy formation puzzle that has proven a significant obstacle. Herschel is satisfying a long awaited demand for a sensitive, high resolution facility to rapidly survey the sky in the sub-millimetre and finally detect a significant proportion of this elusive population.

The first part of the programme exploits the fact that the sub-millimetre is extraordinarily well suited to detecting gravitational lenses. The Herschel survey data will contain around 500 new strong lens systems out to a distance looking back over two thirds of the Universe's age. The first milestone is to identify and characterise galaxies acting as lenses to produce the largest and most distant sample to date. Secondly, applying a powerful reconstruction technique developed by the author to the lenses to measure mass profiles, the morphology of the baryons and the dark matter will be measured (in some cases separately) to investigate their evolution over the last 70% of the Universe's history. This is an exceptional opportunity to constrain models of structure formation in a way that has not been feasible until now.

Lensing also magnifies the flux of background objects above the detection threshold. Therefore, in addition to studying the evolution of the lenses themselves, the sample will be used to probe the population of dusty sources fainter than the survey sensitivity. Furthermore, using the aforementioned reconstruction technique, highly magnified undistorted surface brightness maps of each source will be computed to analyse in detail the morphology of the faint (and therefore generally more distant) dusty sources. Finally, the lens sample will place the most restrictive lensing limits on the cosmological model to date in a way that is complementary to other methods.

The second part of the fellowship programme will apply a new method for optimally measuring the evolution in luminosity of the hundreds of thousands of new Herschel sources detected. This will be combined with the framework established over several years by the author to finally provide a definitive study of the link between local systems and the dusty star forming galaxies that prevailed when the Universe was only 40% of its current age. Specifically, this involves measuring the growth of stellar mass and evolution of star formation in sub-millimetre galaxies (using another new method developed for reconstructing star formation histories) and measuring their transformation into other galaxy types as they evolve.

In terms of scale and viability of the programme, the Herschel data account for an impressive 1500 hours of observations over 700 square degrees of sky. This reflects a large investment from the UK astronomical community and one which must be justified by maximising scientific exploitation and impact.

Publications

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Agius N (2015) H-ATLAS/GAMA and HeViCS - dusty early-type galaxies in different environments in Monthly Notices of the Royal Astronomical Society

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Amvrosiadis A. (2018) ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm in Monthly Notices of the Royal Astronomical Society

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Bakx T (2018) The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations in Monthly Notices of the Royal Astronomical Society

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Bakx Tom J. L. C. (2018) The Herschel Bright Sources (HerBS): sample definition and SCUBA-2 observations in Monthly Notices of the Royal Astronomical Society

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Bourne N (2016) The Herschel -ATLAS Data Release 1 - II. Multi-wavelength counterparts to submillimetre sources in Monthly Notices of the Royal Astronomical Society

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Bourne N. (2016) The Herschel-ATLAS Data Release 1 - II. Multi-wavelength counterparts to submillimetre sources in Monthly Notices of the Royal Astronomical Society

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Clark C (2015) Herschel -ATLAS: the surprising diversity of dust-selected galaxies in the local submillimetre Universe in Monthly Notices of the Royal Astronomical Society

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De Geyter G (2015) Dust energy balance study of two edge-on spiral galaxies in the Herschel-ATLAS survey in Monthly Notices of the Royal Astronomical Society

 
Description To date, there are two key outcomes that result from the fellowship. First, a new technique for reconstructing interferometric data of gravitationally lensed sources has been developed. This is aimed specifically at the analysis of large forthcoming dataset produced by the ALMA interferometric array. This method has now been applied successfully to a new sample of strong gravitational lenses imaged with ALMA. The results are published (Dye et al., 2018, MNRAS, 476, 4383) and shed new light on the star formation processes in galaxies in the early universe. Secondly, the fellowship has resulted in the first release of data acquired by the UKIRT Hemisphere Survey (UHS), a multi-national collaboration to survey almost all of the northern hemisphere in the near-infrared (J and K band). As project scientist, I have managed survey operations since its beginning in 2011. During late 2017 and early 2018, I prepared the full set of 13,000 square degrees of J-band survey data, including images and catalogues, for their first release to the world-wide astronomical community in August 2018. The UHS is the largest near-infrared database to exist at present. See the UHS DR1 paper for further details: Dye et al., 2018, MNRAS, 473, 5113.
Exploitation Route Publication of the new lens modelling method has allowed many other groups around the world to fully exploit strong lens interferometric data. The UHS data release provides a large legacy database for years to come for galactic and extra-galactic astronomers alike.
Sectors Other

 
Description The lensed image reconstruction algorithm used in the fellowship turns out to be immediately applicable to the reconstruction of MRI images. This has therefore motivated collaboration with the MRI group here at the University of Nottingham to better explore potential gains in MRI imaging. This work is ongoing.
First Year Of Impact 2015
Sector Healthcare
Impact Types Societal

 
Description 3 year post-doctoral research associate funding
Amount £90,159 (GBP)
Funding ID ST/P000614/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 08/2017 
End 05/2020
 
Description PhD Studentship
Amount £66,000 (GBP)
Funding ID ST/S505602/1 
Organisation University of Nottingham 
Sector Academic/University
Country United Kingdom
Start 09/2018 
End 04/2022
 
Title Herschel ATLAS 1st data release 
Description This is the data release made by the Herschel ATLAS consotium. The data have undergone extensive processing, testing, and characterisation. The specific contribution to this dataset made in this award is the assignment of optical counterparts to the sub-millimetre sources detected in the H-ATLAS survey 1st data release. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
Impact This is a large and unique dataset which has been made publically available. The legacy value of the dataset is very high and as such it will be used in many different areas of astronomy. 
URL http://www.h-atlas.org
 
Title Herschel ATLAS 2nd data release 
Description This is the second data release made by the 300-person strong international Herschel ATLAS consotium. My specific contribution to this dataset made in this award is the assignment of optical counterparts to the sub-millimetre sources detected in H-ATLAS. This has led to a publication (Furlanetto, Dye, et al. 2018) 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact These data constitute one of the largest area surveys conducted at sub-millimetre wavelengths. The data release includes images and source catalogues. Data have been released globally and are already having a major impact in studies of high redshift galaxies. See Eales et al, 2010, PASP, 122, 499 for an indication of the impact of the H-ATLAS dataset (at the time of writing, there were 330 citations to this paper which largely stem from DR1). 
URL http://www.h-atlas.org
 
Title The UKIRT Hemisphere Survey public data release 
Description The UKIRT Hemisphere Survey (UHS) is a survey of most of the northern hemisphere in the near-infrared (J and K band). I am the project scientist. The UHS has been surveying the sky for seven years and made its first data release of J band imaging and source catalogues in August 2017. This is the largest near-infrared database to exist at present. The data were released to an international consortium including all UK institutes, The University of Hawaii, The University of Arizona and Lockheed Martin. The data were made publicly available in a world-wide release in August 2018. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact The UHS, like its optical equivalent, the Sloan Digital Sky Survey, will provide a large legacy database for years to come for galactic and extra-galactic astronomers alike. 
URL http://wsa.roe.ac.uk/uhsDR1.html
 
Title UKIRT Hemisphere Survey 
Description The UKIRT Hemisphere Survey (UHS) is a survey of most of the northern hemisphere in the near-infrared (J and K band). I am the project scientist. The UHS has been surveying the sky for six years and made its first data release of J band imaging and source catalogues in August 2017. This is the largest near-infrared database to exist at present. The data are presently released to an international consortium including all UK institutes, The University of Hawaii, The University of Arizona and Lockheed Martin. The data will become public in August 2018. 
Type Of Material Database/Collection of data 
Year Produced 2017 
Provided To Others? Yes  
Impact The UHS, like its optical equivalent, the Sloan Digital Sky Survey, will provide a large legacy database for years to come for galactic and extra-galactic astronomers alike. 
URL http://wsa.roe.ac.uk/uhsDR1.html
 
Description HerMES - Herschel Multi-tiered Extragalactic Survey 
Organisation University of Sussex
Country United Kingdom 
Sector Academic/University 
PI Contribution Head of optical and near-IR working group. Contributions to strong gravitational working group and associated publications.
Collaborator Contribution This is a multi-national collaboration with Sussex as the PI institute.
Impact Tens of research papers have been produced by the HerMES collaboration.
Start Year 2012
 
Description Herschel ATLAS - Cardiff 
Organisation Cardiff University
Department School of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution Scientific Research Collaboration
Collaborator Contribution Scientific Research Collaboration
Impact Scientific Research Collaboration
Start Year 2009
 
Description LSST Dark Energy Science Collaboration 
Organisation Stanford University
Country United States 
Sector Academic/University 
PI Contribution This is a new collaboration. I have been granted 'LSST Affiliate PI status' for three years until 2020, coinciding with the end of this fellowship. The collaboration has been initiated on the understanding that I will bring new techniques to solve the problem of finding strong gravitational lens systems in the vast image data that the new LSST telescope will produce. I also plan to help work towards an automated pipeline for modelling these new systems, to vastly increase our knowledge of galaxy structure, dark matter content in galaxies and how these evolve as the Universe ages.
Collaborator Contribution This is a collaboration involving hundreds of partners spread across the world. The LSST is a new telescope which will produce optical imaging of large areas of the sky. The images will be analysed by many different 'science collaborations' with many different aims, each falling under the umbrella of the LSST consortium.
Impact None yet - collaboration has just started.
Start Year 2017
 
Description LSST Dark Energy Science Collaboration 
Organisation University of Oxford
Country United Kingdom 
Sector Academic/University 
PI Contribution This is a new collaboration. I have been granted 'LSST Affiliate PI status' for three years until 2020, coinciding with the end of this fellowship. The collaboration has been initiated on the understanding that I will bring new techniques to solve the problem of finding strong gravitational lens systems in the vast image data that the new LSST telescope will produce. I also plan to help work towards an automated pipeline for modelling these new systems, to vastly increase our knowledge of galaxy structure, dark matter content in galaxies and how these evolve as the Universe ages.
Collaborator Contribution This is a collaboration involving hundreds of partners spread across the world. The LSST is a new telescope which will produce optical imaging of large areas of the sky. The images will be analysed by many different 'science collaborations' with many different aims, each falling under the umbrella of the LSST consortium.
Impact None yet - collaboration has just started.
Start Year 2017
 
Description UKIRT Hemisphere Survey 
Organisation Royal Observatory Edinburgh
Country United Kingdom 
Sector Public 
PI Contribution I am the project scientist.
Collaborator Contribution Data reduction, data processing, online archiving, data quality control.
Impact Data release 1 made in August 2017 to consortium members (UK, University of Hawaii, University of Arizona and Lockheed martin). World-wide release in August 2018.
Start Year 2011
 
Description UKIRT Hemisphere Survey 
Organisation University of Arizona
Department Department of Physics
Country United States 
Sector Academic/University 
PI Contribution I am the project scientist.
Collaborator Contribution Data reduction, data processing, online archiving, data quality control.
Impact Data release 1 made in August 2017 to consortium members (UK, University of Hawaii, University of Arizona and Lockheed martin). World-wide release in August 2018.
Start Year 2011
 
Description UKIRT Hemisphere Survey 
Organisation University of Cambridge
Department Institute of Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution I am the project scientist.
Collaborator Contribution Data reduction, data processing, online archiving, data quality control.
Impact Data release 1 made in August 2017 to consortium members (UK, University of Hawaii, University of Arizona and Lockheed martin). World-wide release in August 2018.
Start Year 2011
 
Description UKIRT Hemisphere Survey 
Organisation University of Hawaii
Department Institute for Astronomy
Country United States 
Sector Academic/University 
PI Contribution I am the project scientist.
Collaborator Contribution Data reduction, data processing, online archiving, data quality control.
Impact Data release 1 made in August 2017 to consortium members (UK, University of Hawaii, University of Arizona and Lockheed martin). World-wide release in August 2018.
Start Year 2011
 
Description UKIRT Hemisphere Survey 
Organisation University of Hertfordshire
Department School of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution I am the project scientist.
Collaborator Contribution Data reduction, data processing, online archiving, data quality control.
Impact Data release 1 made in August 2017 to consortium members (UK, University of Hawaii, University of Arizona and Lockheed martin). World-wide release in August 2018.
Start Year 2011
 
Title Adaptive semi-linear inversion 
Description This is a new algorithm, now published, which is used to reconstructed the gravitationally lensed image of a background source. The agorithm supercedes older methodolgies which have associated problems and biases. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2015 
Impact We are aware that several research groups around the world have adopted our new algorithm. 
 
Title Adaptive semi-linear modelling in the uv-plane 
Description This is a new technique to directly model strong gravitational lens interferometric data. New code allows modelling of uv-plane data without the need to first transform to the image plane. This alleviates many potential biases which can result from having to transform to the image plane. The method has been described in Dye et al. 2018, arXiv:170505413, MNRAS in press (at the time off writing). 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2018 
Impact This new technique is being used by several strong lensing groups around the world. 
 
Title AutoLens 
Description AutoLens is a new piece of strong gravitational lensing code to be made publically available in 2018. AutoLens is the result of three years of development with my PhD student, James Nightingale at Nottingham University. The code is designed to automate the modelling of a new sample of thousands of strong gravitational lens images, a task that is impossible to complete manually. James now works at Durham University but our collaboration is continuing as new features are added to the software. 
Type Of Technology Software 
Year Produced 2018 
Impact We are aware of several groups around the world now using the software to carry out their research. Expectations are that AutoLens will reach an increasingly wide scientific audience and be the standard tool of choice in the future of lens modelling for forthcoming surveys such as those produced by LSST and Euclid. 
URL https://github.com/Jammy2211/PyAutoLens
 
Description Astronomical society talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Multiple talks to Astronomical and other Scientific Societies


Public Engagement
Year(s) Of Engagement Activity 2010,2011,2012,2013,2014
 
Description Public talks 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact This entry represents multiple talks given to the general public on astronomical themes. These include events held during university open days, specific outreach events like 'Pint of Science' and 'Skeptics in the pub' and the Nottingham public lecture series.
Year(s) Of Engagement Activity 2014,2015,2016,2017,2018
 
Description School visits 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact This single entry represents several tens of duplicated events across local schools in the Nottingham region. Events usually entail giving a powerpoint presentation.


Inspiring the younger generation of potential scientists
Year(s) Of Engagement Activity 2011,2012,2013,2014,2015