LOFAR-UK: Request for Continued Funding, 2021-2024, and LOFAR2.0 Upgrade

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Physics and Astronomy

Abstract

The Low Frequency Array (LOFAR) is a new-generation radio telescope operating at low radio frequencies, between about 30 and 240 MHz. With a sensitivity more than 100 times better than any previous telescope at these frequencies, high precision imaging capabilities, and an enormous field of view, LOFAR is by far the most powerful 100 MHz telescope on the planet. It is revolutionising our view of the low-frequency radio Universe.

LOFAR has an extremely broad and diverse science case, ranging from cosmological studies of the nature of the early Universe to understanding the physics of our own Sun and the impact of Solar activity on the Earth's environment. It is carrying out detailed studies of the formation and lifecycles of galaxies, and of the supermassive black holes within them that can reach a billion times the mass of our own Sun. It is allowing the study of the laws of physics in some of the most extreme astrophysical environments. With its wide range of capabilities, it attracts a very broad user community and has impact on many of STFC's strategic priorities.

LOFAR is an inherently international project. The core of the LOFAR array is located in the Netherlands, but receiver stations are spread around 8 partner countries in Europe, including the UK station at Chilbolton Observatory. The international stations greatly improve the imaging precision, and hence the scientific capability of the array.

This grant is concerned with retaining the UK's leading involvement in LOFAR for the next three years, through annual subscription fees, and the operation, maintenance and data transport for the UK LOFAR station. It will also support UK involvement in an on-going upgrade to LOFAR, known as LOFAR2.0, which will greatly increase the capabilities of the array at lower frequencies, and open up a wealth of new science goals.

Publications

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Alegre L (2022) A machine-learning classifier for LOFAR radio galaxy cross-matching techniques in Monthly Notices of the Royal Astronomical Society

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Barkus B (2022) The application of ridgelines in extended radio source cross-identification in Monthly Notices of the Royal Astronomical Society

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Boyde B (2022) Lensing from small-scale travelling ionospheric disturbances observed using LOFAR in Journal of Space Weather and Space Climate

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Chen X (2023) The frequency ratio and time delay of solar radio emissions with fundamental and harmonic components in Monthly Notices of the Royal Astronomical Society

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Clarkson D (2021) First Frequency-time-resolved Imaging Spectroscopy Observations of Solar Radio Spikes in The Astrophysical Journal Letters

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Cochrane R (2023) The LOFAR Two-metre Sky Survey: the radio view of the cosmic star formation history in Monthly Notices of the Royal Astronomical Society

 
Title LOFAR Two-metre Sky Survey (LoTSS) DR2 
Description VizieR online Data Catalogue associated with article published in journal Astronomy & Astrophysics with title 'The LOFAR Two-metre Sky Survey (LoTSS). V. Second data release.' (bibcode: 2022A&A...659A...1S) 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact This catalogue has been very widely used, with currently over 100 citations per year. 
URL https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/659/A1
 
Title The LOFAR Two-Metre Sky Survey (LoTSS): VI. Optical identifications for the second data release 
Description The second data release of the LOFAR Two-Metre Sky Survey (LoTSS) covers 27% of the northern sky, with a total area of $\sim 5,700$ deg$^2$. The high angular resolution of LOFAR with Dutch baselines (6 arcsec) allows us to carry out optical identifications of a large fraction of the detected radio sources without further radio followup; however, the process is made more challenging by the many extended radio sources found in LOFAR images as a result of its excellent sensitivity to extended structure. In this paper we present source associations and identifications for sources in the second data release based on optical and near-infrared data, using a combination of a likelihood-ratio cross-match method developed for our first data release, our citizen science project Radio Galaxy Zoo: LOFAR, and new approaches to algorithmic optical identification, together with extensive visual inspection by astronomers. We also present spectroscopic or photometric redshifts for a large fraction of the optical identifications. In total 4,116,934 radio sources lie in the area with good optical data, of which 85% have an optical or infrared identification and 58% have a good redshift estimate. We demonstrate the quality of the dataset by comparing it with earlier optically identified radio surveys. This is by far the largest ever optically identified radio catalogue, and will permit robust statistical studies of star-forming and radio-loud active galaxies. 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
Impact Optical IDs for several million radio sources 
URL https://arxiv.org/abs/2309.00102
 
Description ROE Open Weekends and other ROE visitor centre activities 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Open weekend at Royal Observatory. Annual event, attracting up to 3000 people. IfA staff and postdoc present research, including funded from this grant. Feedback is excellent.
Additional engagement in other ROE Visitor Centre activities such as 'Astronomy for All' talk series (which reach hundreds of people), and school visits. The ROE Visitor Centre programme directly reaches around 9,000 members of the public annually, including nearly 2,500 schoolchildren through many tens of school visits.
Year(s) Of Engagement Activity 2021,2022,2023,2024
URL https://www.eventbrite.com/cc/public-events-at-royal-observatory-edinburgh-1008419