228 Projects, page 1 of 46
The Gaia project is making an all-sky astrometric survey. As part of the Gaia data release 3 during summer 2022 astrometric accelerations will become available for the first time. This will enable an entirely new route to identify brown dwarfs and planets. The follow-up both using archival and new data will be concerned with the identification, characterisation and constraints on orbital parameters. This study will be part of the wider follow-up effort identifying new brown dwarfs and taking follow-up spectra. Spectra for all brown dwarfs in Gaia can be used along with kinematic information from Gaia to interpret their chemical compositions and ages. These will be used alongside the Gaia information in particular also low resolution spectra which is envisaged as a possible data product in future data releases. Scientific exploitation of the Gaia sample will enable a much more secure understanding of brown dwarfs and may include derivation of the local luminosity and mass function, characterisation of benchmarks and correlations analyses of physical parameters such as age/mass with photometric/spectroscopic features. This project is envisaged to include the student becoming a member of the Gaia consortium and also being concerned with the data quality produced for future Gaia data releases.
The operation of the SKA Observatory assumes the existence of SKA Regional Centres (SRCs) to deliver a range of support to the science community. The SRCs are required in order to provide the main portal for scientists to access the SKA including provision of computing resources and support to enable the science user community to analyse and extract science from data products produced by the SKA. An SRC Network (SRCNet) will be made up of SRCs distributed around the world in SKA Member countries. Each SRC will be required to conform to agreed standards in protocols, data architecture and information management policies to ensure that they appear as a single federated entity to SKA users. The SRCNet will provide a collection of both services and infrastructure that will comprise a global capability to distribute, process and curate the data from the SKA telescopes. The SRCNet will provide the basic governance and operational model and structures, and the baseline functionality of the SRC network. SKAO member states and SRC stakeholders are already engaging in the design of the SRC Network. In order to enable the greatest possible return to the UK from its investment in the SKA, both scientific and within the data intensive supercomputing / big data / data science technical work, it is essential for the UK to fully participate and contribute to the SRCNet Project. The UK SKA Rregional Centre (UKSRC) Forum has helped generate the SRCNet's basic requirements and high level architecture. The next Phase, which begins in April 2022, is to refine the architecture and produce a verified system architecture based on advanced requirements. The four main Work Packages (WPs) needed to deliver this are:- WP1 Refined high-level architecture, which includes the requirements that describe the specifics of implementation WP2 Detailed component architecture (including interfaces and protocols). WP3 Verified technologies to be used in the implementation. WP4 Limited functional, but demonstrable prototypes that are tested and verified against our basic requirements. Resources are sought to allow the UK to participate fully in these 4 WPs to allow the UK to play a leading role in the design of the SRCNet. This will be particularly accomplished by participation in WP4, the prototyping programme. There are 5 prototyping projects; these will enable (i) Data products replication, distribution, and synchronization across multiple locations; (ii) the creation of a Federated Authentication and Authorization API and proto-Identity Management service; (iii) Data Processing Notebooks; (iv) Visualization of SKA data with high volume of users and high amount of data; and (v) a service for the distribution of software, tools and services. To help deliver this the UKSRC Forum requests the following for the period April-September 2022 inclusive; 6 FTE of research software engineering, data steward and research devops effort; two FTE of Project Manager support to make sure the UK delivers its outputs; a 0.5FTE SRC Project Coordinator and a 0.5FTE Project Scientist to implement the strategy and project plan, and the day to day running of the Project - they will also oversee 2 UKSRC work packages, WP0: Set up UKSRC Governance and Management structure and WP5: Direction and Management of the Project, and the generation of reports. In addition £10k is requested for T&S to allow attendance at meetings and conferences to help progress WPs 1-4. These resources will in effect create the first elements of the proto-UKSRC node. This will create a basic infrastructure that allows the UK to take a leading role the development of the SRCNet, and also allows the UK SKA Science Community access to UKSRC services that will allow them to create, develop and refine software technologies and workflows that will allow the UK to maximise its exploitation of SKA data, both during the commissioning phase (2024-27) and the production phase (2028-).
The interaction of aerosol with clouds leads to the so called aerosol indirect effect. As the size distribution and chemical composition of aerosol entering clouds change, the structure and lifetime of cloud systems changes. Some of these changes in aerosol properties are man made as the amount and chemical composition of emissions change. These effects are the largest uncertainty in quantifying future climate change. A particular gap in our knowledge is to understand the way in which aerosol particles affect the properties of ice, and mixed ice and liquid water, clouds. Among other substances such as dust and organic material, it is thought that black carbon-containing aerosol (soot) maybe an important ice nucleus in some conditions. Black carbon is also very important in affecting the radiative properties of cloud as it acts as an absorbing material for solar radiation. In determining its effectiveness both as an ice nucleus and as an absorber it is very important as to whether it is incorporated into cloud particles or not. In this project we aim to address the issues of the effectiveness of a wide range of aerosol types as the centres on which liquid droplets form and also their ability to act as centres to initiate the formation of ice crystals in clouds below 0C by using a mixture of techniques. Airborne insitu measurements of the type number and size of ice particles and water droplets in clouds will be made and the aircraft will also make measurements of the size distribution and chemical composition of aerosol, particles below and above the cloud layers. Remote sensing using the Chilbolton Radar and Lidar, whilst the aircraft is flying in the vicinity will give a simultaneous view of the larger scale cloud structure and aerosol properties below cloud. Ground based measurements of aerosol properties will give a more detailed view of the aerosol properties that can be achieved on the aircraft. Studies in a cold chamber in Germany will enable us to measure the ice nucleating properties of a very wide range of particles that occur in our detailed studies and more generally world-wide. In order to get a more general view of the cloud structures that occur longer-term measurements will be made with the Chilbolton radars and Lidars coupled with ground based measurements of the aerosol properties. Detailed modelling of the cloud formation on the aerosols, particularly the ability of the aerosols to produce water droplets and ice crystals will link all these observations and the cold chamber studies. The ability of the model to reproduce the detailed structure of the cloud, the ice crystals and the liquid water together with the precipitation will be tested by comparing the model predictions with the observations from the aircraft and radar. The model input will be the atmospheric structure (vertical profiles of temperature, wind and humidity) and the aerosol measured below cloud. Having incorporated our new understanding of the links between aerosol and cloud properties in our detailed field programme into our cloud model, this model will be used, in conjunction with satellite data, to better understand the influence of aerosol on mixed phase (ice and water clouds) globally. In this way we will establish the first global treatment of ice nuclei based on aerosol properties. We will establish remaining uncertainties in this issue. This will be a step towards a fuller treatment of the role of aerosol particles on ice and mixed phase clouds.
The Centre for Astrophysics Research carries out observational programmes spanning the wavelength range from X-ray to radio -- supporting this by computer modelling and simulation. Our research ranges from observations of high-redshift galaxies at long wavelengths through to novel statistical analyses of observations seeking to detect planets outside our Solar System. In between these extremes, we carry out the largest multi-wavelength surveys conducted to date to understand the properties of the Milky Way. Our research makes use of observations from all of the main European and international astronomical observatories, including ground-based observatories at optical, radio and submillimetre wavelengths, and space observatories at wavelengths ranging from the far infrared to X-rays. Computer simulations gives us a better understanding of the physical processes detected in our observations, and we need to apply advanced data-mining techniques to work with the ~terabyte datasets we are generating. Below is a brief description of our research in each of these areas. We perform searches of nearby stars to discover planets, and are world leaders in the application of radial-velocity methods for this purpose; our focus in the grant period will be the planet populations around Sun-like nearby stars. We also discover, follow up and model the properties of the coolest brown dwarfs whose temperatures overlap with those of planets. These studies aim to understand the diversity of the population of brown dwarfs detected with the Gaia satellite and to establish how their modes of formation fit in with those of their brethren of different masses, i.e. heavier (stars) or lighter (planets). The Milky Way is our home galaxy. Material within it, in the form of gas and dust, is the raw material for forming stars and planetary systems. At the end of stellar lives some of this material remains locked up in stellar remnants but much of it is returned in late superwind phases and supernova explosions. The cycle between accretion in youth and outflow in old age enriches the gaseous medium and governs its dynamics, via the thermal and mechanical energy injected into the gas. By using large area imaging surveys, our research looks at how gas, dust and stars within the Milky Way are connected, and at the details of how stars are formed. Our surveys span the optical to radio domains, tracing stars, extinction, molecular clouds, their dust properties and associated star formation. Looking beyond the Milky Way, it is possible to appraise how stars form and evolve in different environments, from small dwarf galaxies to the outer parts of other galaxies like our own. We study the gas content of galaxies, providing the material for star formation, and link what we find to stellar populations and to star forming regions in the full range of local galaxies. By understanding the processes that trigger star formation and stellar evolution in the nearby Universe, we can apply this understanding to the very earliest galaxies and the first generations of stars in the distant Universe. Indeed some of our work focuses on high-redshift galaxies detected with great efficiency at sub-millimetre wavelengths, making use of cutting-edge instruments such as ALMA. A new generation of surveys is mapping out the most distant galaxies, and allows us to investigate what links the processes of star formation and the growth of supermassive black holes. We also use detailed radio and X-ray observations, along with computer modelling, to measure the energy injected by jets ejected from supermassive black holes into distant galaxies and clusters of galaxies, affecting star formation and gas properties, and playing a long-term role in their evolutionary history. The evolution of the chemical elements in these galaxies, and the interplay between black-hole activity and elemental abundances, is a particular focus of this proposal.
The WEAVE-LOFAR survey is spending five years from 2021 obtaining more than a million spectra of sources identified in the LOFAR Two-metre Sky Survey (LoTSS) using the new William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE) instrument. Marina's doctorate is focussed on preparing for, and the scientific exploitation of WEAVE-LOFAR in the field of star forming galaxies and active galactic nuclei.