The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2

We present the final 6″ resolution data release of the ELAIS-N1 field from the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey Deep Fields project (LoTSS Deep). The 144 MHz images are the most sensitive achieved to date at this frequency and were created from 290 TB of data obtained from 505 h on-source observations taken over 7.5 years. The data were processed following the strategies developed for previous LoTSS and LoTSS Deep data releases. The resulting images span 24.53 square degrees, and using a refined source detection approach, we identified 154 952 radio sources formed from 182 184 Gaussian components within this area. The maps reach a noise level of 10.7 μJy beam −1 at 6″ resolution, where approximately half of the noise is due to source confusion. In about 7.4% of the image, our limited dynamic range around bright sources results in a further > 5% increase in the noise. The images have a flux density scale accuracy of about 9%, and the standard deviation of offsets between our source positions and those from Pan-STARRS is 0.2″ in RA and Dec for high significance detections. We searched individual epoch images for variable sources, identifying 39 objects with considerable variation. We also searched for circularly polarised sources, achieving three detections of previously known emitters (two stars and one pulsar) whilst constraining the typical polarisation fraction plus leakage to be less than 0.045%.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-02-08
DOI
https://doi.org/10.1051/0004-6361/202452930
Citations
6
Primary Topic
Geophysics and Gravity Measurements
Type
article
Field-Weighted Citation Impact
10.76

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article

The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2

T. W. Shimwell, A. Drabent, A. Botteon, J. Sabater et al.
6 citations
Astronomy and Astrophysics
Geophysics and Gravity Measurements
10.76
article

The LOFAR Two-metre Sky Survey: Deep Fields Data Release 2

T. W. Shimwell, A. Drabent, A. Botteon, J. Sabater, M Brüggen, L. K. Morabito, J. M. G. H. J. de Jong, J. R. Callingham, H. J. A. Röttgering, Gian Luca Brunetti, C. Tasse, R. Kondapally, I. Prandoni, K. Małek, C. Horellou, K. J. Duncan, A. Bonafede, W. L. Williams, Iris de Ruiter, M. Bondi, Dhanya G. Nair, D. J. B. Smith, R. J. van Weeren, Seethalakshmi Iyer, M. J. Hardcastle, C. L. Hale, Frits Sweijen, Vibor Jelić, A. Rowlinson, F. de Gasperin, A. Shulevski, P. N. Best
article en
6 citations

Abstract

We present the final 6″ resolution data release of the ELAIS-N1 field from the LOw-Frequency ARray (LOFAR) Two-metre Sky Survey Deep Fields project (LoTSS Deep). The 144 MHz images are the most sensitive achieved to date at this frequency and were created from 290 TB of data obtained from 505 h on-source observations taken over 7.5 years. The data were processed following the strategies developed for previous LoTSS and LoTSS Deep data releases. The resulting images span 24.53 square degrees, and using a refined source detection approach, we identified 154 952 radio sources formed from 182 184 Gaussian components within this area. The maps reach a noise level of 10.7 μJy beam −1 at 6″ resolution, where approximately half of the noise is due to source confusion. In about 7.4% of the image, our limited dynamic range around bright sources results in a further > 5% increase in the noise. The images have a flux density scale accuracy of about 9%, and the standard deviation of offsets between our source positions and those from Pan-STARRS is 0.2″ in RA and Dec for high significance detections. We searched individual epoch images for variable sources, identifying 39 objects with considerable variation. We also searched for circularly polarised sources, achieving three detections of previously known emitters (two stars and one pulsar) whilst constraining the typical polarisation fraction plus leakage to be less than 0.045%.

Astronomy and AstrophysicsVol. 695
Leiden University (NL), Centre National de la Recherche Scientifique (FR), University of Hertfordshire (GB), Universität Hamburg (DE), University of Groningen (NL), University of Concepción (CL), Durham University (GB), Rhodes University (ZA), Université Paris Sciences et Lettres (FR), Observatoire de Paris (FR), University of Oxford (GB), National Centre for Nuclear Research (PL), Galaxies, Etoiles, Physique et Instrumentation (FR), Royal Observatory (GB), SKA Observatory (GB), Istituto di Radioastronomia di Bologna (IT), Ruđer Bošković Institute (HR), Thüringer Landessternwarte Tautenburg (DE), Max Planck Institute for Radio Astronomy (DE), UK Astronomy Technology Centre (GB), Chalmers University of Technology (SE), University of Amsterdam (NL), Netherlands Institute for Radio Astronomy (NL), University of Bologna (IT), University of Edinburgh (GB)
UK Research and Innovation, Leverhulme Trust, European Commission, University of Hertfordshire, Science Foundation Ireland, Deutsche Forschungsgemeinschaft, Bundesministerium für Bildung und Forschung, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Max-Planck-Gesellschaft, Centre National de la Recherche Scientifique, Université d'Orléans, Ministerium für Innovation, Wissenschaft und Forschung des Landes Nordrhein-Westfalen, Gauss Centre for Supercomputing, Observatoire de Paris, Université de Recherche Paris Sciences et Lettres, Science and Technology Facilities Council, DST-NRF Centre Of Excellence In Tree Health Biotechnology
Openalex Percentile: Top 2%
Geophysics and Gravity Measurements
10.76
DOIOpen Access PDFOpenAlex
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