Measuring Dark Matter, Neutral Hydrogen and Neutrino Mass with Next Generation Weak Lensing and Radio Data
Lead Research Organisation:
Liverpool John Moores University
Department Name: Astrophysics Research Institute
Abstract
My research aims at measuring fundamental properties of three extremely elusive substances: dark matter, dark energy and neutrinos. As recently discovered, neutrinos are massive particles (Nobel Prize 2015), but their actual mass is still unknown. While we now understand how dark matter interacts with gravity, we still do not know what it is, and different cosmological measurements disagree about its abundance. Furthermore, all aspects of the dark energy are highly uncertain.
This situation will change drastically with the upcoming generation of galaxy surveys such as Euclid, LSST and WFIRST. These dedicated observatories will measure properties of dark matter, dark energy and neutrinos based on their "weak gravitational lensing" signatures. This technique relies on the detection of small distortions imparted on the image of distant galaxies by the gravitational pull of foreground massive objects. Weak lensing measures the abundance and the clustering of the total foreground matter, which is uniquely affected by its different elements.
I will use the latest observations from the Kilo Degree Survey, which has started to deliver exquisite weak lensing data, and will push the frontiers of our knowledge about the Universe, its content and its initial conditions. Through combining these dark matter data with independent observations of the cosmic microwave background and of the hydrogen, I will map out the global content of our Universe, component-by-component. This will be achieved with the method of 'cross-correlations', which singles out species common two both datasets.
These are transforming times for the field of cosmology, and the fundamental research undertaken during this Fellowship will by central to our understanding of dark matter, neutrinos, hydrogen and dark energy.
The expected outcome of the research includes the combined analyses of two lensing data sets, cosmic microwave background observations, and three dimensional maps of neutral hydrogen. It will result in at least five first-authored papers, plus a number of contributions based on sharing the simulations products that will be produced. This will directly support the future analysis of a number of scientific investigations, aiming for an impact well beyond 2030.
This situation will change drastically with the upcoming generation of galaxy surveys such as Euclid, LSST and WFIRST. These dedicated observatories will measure properties of dark matter, dark energy and neutrinos based on their "weak gravitational lensing" signatures. This technique relies on the detection of small distortions imparted on the image of distant galaxies by the gravitational pull of foreground massive objects. Weak lensing measures the abundance and the clustering of the total foreground matter, which is uniquely affected by its different elements.
I will use the latest observations from the Kilo Degree Survey, which has started to deliver exquisite weak lensing data, and will push the frontiers of our knowledge about the Universe, its content and its initial conditions. Through combining these dark matter data with independent observations of the cosmic microwave background and of the hydrogen, I will map out the global content of our Universe, component-by-component. This will be achieved with the method of 'cross-correlations', which singles out species common two both datasets.
These are transforming times for the field of cosmology, and the fundamental research undertaken during this Fellowship will by central to our understanding of dark matter, neutrinos, hydrogen and dark energy.
The expected outcome of the research includes the combined analyses of two lensing data sets, cosmic microwave background observations, and three dimensional maps of neutral hydrogen. It will result in at least five first-authored papers, plus a number of contributions based on sharing the simulations products that will be produced. This will directly support the future analysis of a number of scientific investigations, aiming for an impact well beyond 2030.
People |
ORCID iD |
Joachim Harnois-Deraps (Principal Investigator / Fellow) |
Publications
Schneider P
(2022)
Pure-mode correlation functions for cosmic shear and application to KiDS-1000
in Astronomy & Astrophysics
Robertson Naomi Clare
(2020)
Strong detection of the CMB lensingxgalaxy weak lensingcross-correlation from ACT-DR4,PlanckLegacy and KiDS-1000
in arXiv e-prints
Robertson N
(2021)
Strong detection of the CMB lensing and galaxy weak lensing cross-correlation from ACT-DR4, Planck Legacy, and KiDS-1000
in Astronomy & Astrophysics
Martinet Nicolas
(2020)
Probing dark energy with tomographic weak-lensing aperture mass statistics
in arXiv e-prints
Martinet Nicolas
(2020)
Impact of baryons in cosmic shear analyses with tomographic aperture mass statistics
in arXiv e-prints
Martinet N
(2021)
Impact of baryons in cosmic shear analyses with tomographic aperture mass statistics
in Astronomy & Astrophysics
Description | I have led a team of computational cosmologists in the development of novel methods to extract information about cosmological parameters from cosmic shear data. This was mostly done on state-of-the-art simulations. The next step is to apply this on real data (see next award). |
Exploitation Route | Most of the codes are open source, and publicly available on github, which means our methods are transparent and can be used by other teams. Most of the simulation products are also publicly available. |
Sectors | Education |
Title | Public simulations of the Dark Energy Survey |
Description | I created a large suite of weak lensing simulations that reproduce the key properties of the Dark Energy Survey Year-1 data, which I have use to directly infer the cosmological parameters of our Universe. These simulations have multiple purposes; some a used to calibrate the cosmology dependence, some are used to investigate known systematic, while others are used to estimate the uncertainty on the measurement. |
Type Of Material | Improvements to research infrastructure |
Year Produced | 2020 |
Provided To Others? | Yes |
Impact | I have made these simulations publicly available, and two research groups (in Bonn and Munich) are looking at these at the moment, developing novel techniques to extract information about the dark matter and dark energy content of our. |
Description | Durham University |
Organisation | Durham University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | In collaboration with colleagues (already collaborators) from the University of Edinburgh, and based on my expertise in the field, prof. Baojiu Li invited me to contribute to a vast programme of weak lensing simulations tailored for probing deviations from the theory of General Relativity. I am leading the post-processing steps, which turn the raw data into observables, e.g. mock galaxy catalogues that resemble existing and upcoming galaxy surveys. First paper from this collaboration (Arnold et al, 2021) is out on the arXiv and under review. I am expecting to lead on or two papers based on this, the first of which is about 80% complete. |
Collaborator Contribution | Prof. Li and his team are in charge of generating the numerical simulations. Colleagues from Edinburgh will lead some of the statistical analysis. |
Impact | The project involves more than 200 numerical simulations that were run on the DIRAC super computer in Durham. |
Start Year | 2020 |
Description | Lecture on Weak Lensing Beyond Tw0-Point statistics |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | I gave a Lecture to post-graduate students, reviewing the fundamentals of statistics in cosmic shear cosmology data analysis, then further detailing aspect in which I specialise, which are complementary to main stream methods. |
Year(s) Of Engagement Activity | 2021 |
Description | Talk at Tehran Cosmology at the cross-roads Conference |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Other audiences |
Results and Impact | I presented my research results at a Conference in a 10+5 minutes talk. |
Year(s) Of Engagement Activity | 2021 |