Theoretical Cosmology (Summary to follow)

Lead Research Organisation: University of Manchester
Department Name: Physics and Astronomy

Abstract

Theoretical Cosmology

Publications

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Hillier Tom (2018) Radio-Optical Galaxy Shape and Shear Correlations in the COSMOS Field using 3 GHz JVLA Observations in arXiv e-prints

Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N504178/1 01/10/2015 31/03/2021
1789706 Studentship ST/N504178/1 01/10/2016 31/03/2020 Thomas Hillier
 
Description SuperCLASS 
Organisation Commonwealth Scientific and Industrial Research Organisation
Country Australia 
Sector Public 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016
 
Description SuperCLASS 
Organisation The Cyprus Institute
Country Cyprus 
Sector Charity/Non Profit 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016
 
Description SuperCLASS 
Organisation University College London
Country United Kingdom 
Sector Academic/University 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016
 
Description SuperCLASS 
Organisation University of Manchester
Department Jodrell Bank Centre for Astrophysics
Country United Kingdom 
Sector Academic/University 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016
 
Description SuperCLASS 
Organisation University of Texas
Department Department of Astronomy
Country United States 
Sector Academic/University 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016
 
Description SuperCLASS 
Organisation University of Turin
Country Italy 
Sector Academic/University 
PI Contribution SuperCLASS (SuperCLuster Assisted Shear Survey) is a radio weak lensing experiment whose primary aim is to measure the cosmic shear signal from a region of sky containing 5 super clusters using shapes of star-forming galaxies observed by the JVLA and e-MERLIN interferometers. A cluster region was used to enhance the gravitational lensing signal, so that a detection is more likely. The survey also includes data from the Subaru optical telescope as a method to compare outputs. SuperCLASS and the techniques developed as part of it will path the way onto radio weak lensing with the SKA. My work mainly involves using the measured shapes of galaxies measured in the radio and optical bands to extract shear power spectra (optical-optical auto-, radio-optical cross- and radio-radio auto-spectra). These spectra give a measure of the cosmic shear signal. This work also involved using numerical simulations of super-cluster regions to extract error bars for the power spectra.
Collaborator Contribution Partners in the collaboration have worked on: -Data reduction: converting radio observations from their original format (in Fourier space) into real-space images. This also involved creating source catalogues. -Source selection: extracting sources from the radio and optical data, which are believed to be star-forming (elliptically-shaped) galaxies, to form two weak lensing catalogues. -Shape measurement: -Optical: measuring shapes from the optical weak lensing catalogues. Breifly, this involved measuring the point-spread function(s) using stars in the field, and using them to extract galaxy shapes using a model-fitting algorithm. -Radio: Extracting shapes accurately from galaxies measured by radio interferometers is ongoing work. As part of SuperCLASS, 3 shape measurement methods have been developed: one which uses real-space images (see top list item) of galaxies and calibrates the measurements; one which measures galaxy shapes directly from the Fourier plane (original data format); and one which is a hybrid between the previous two, where it grids the Fourier space observations, then images and measures the galaxy shapes. Development of these methods has raised several questions, including the morphology of star-forming galaxies measured at radio wavelengths (different from optical wavelengths). -Measuring other statistical properties of the shear field including aperture mass. -Numerical simulations of cluster fields, with simulated shear signals. -Photometric redshifts of sources using the optical catalogue.
Impact The collaboration has already produced several papers including: -Peters et al. (2016) ArXiv:1612.04247 (Numerical cluster simulations) -Riseley et al. (2016) Arxiv:1607.04056 (GMRT observations of the SuperCLASS region) -Riseley et al. (2018) ArXiv:1711.11199 (Observations of the SuperCLASS region using the Arcminute Microkelvin Imager (AMI) Large Array (LA)) And is currently producing 3 main DR1 papers: -SuperCLASS -- I. Project overview and first data release -SuperCLASS -- II. Weak lensing from radio and optical observations in Data Release 1 -Optical-infrared catalogue & photo-z's
Start Year 2016