Volume 622, February 2019
LOFAR Surveys: a new window on the Universe
|Number of page(s)||21|
|Section||Catalogs and data|
|Published online||19 February 2019|
The LOFAR Two-metre Sky Survey
Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire, College Lane, Hatfield, AL10 9AB UK
2 SUPA, Institute for Astronomy, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ UK
3 School of Physical Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA UK
4 Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
5 ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands
6 CSIRO Astronomy and Space Science, PO Box 1130 Bentley, WA, 6102 Australia
7 Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Kraków, Poland
8 Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH UK
9 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL UK
10 Toruń Centre for Astronomy, Faculty of Physics, Astronomy and Informatics, NCU, Grudziacka 5, 87-100 Toruń, Poland
11 INAF – Istituto di Radioastronomia, Via Gobetti 101, 40129 Bologna, Italy
12 Anton Pannekoek Institute for Astronomy, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam, The Netherlands
13 GEPI, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
14 Department of Physics & Electronics, Rhodes University, PO Box 94, Grahamstown, 6140 South Africa
15 Space Science & Technology Department, The Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0NL UK
16 University of Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
17 Thüringer Landessternwarte (TLS), Sternwarte 5, 07778 Tautenburg, Germany
18 Kapteyn Astronomical Institute, PO Box 800 9700 AV Groningen, The Netherlands
19 Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
Accepted: 9 November 2018
The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120–168 MHz survey of the northern sky with diverse and ambitious science goals. Many of the scientific objectives of LoTSS rely upon, or are enhanced by, the association or separation of the sometimes incorrectly catalogued radio components into distinct radio sources and the identification and characterisation of the optical counterparts to these sources. We present the source associations and optical and/or IR identifications for sources in the first data release, which are made using a combination of statistical techniques and visual association and identification. We document in detail the colour- and magnitude-dependent likelihood ratio method used for statistical identification as well as the Zooniverse project, called LOFAR Galaxy Zoo, used for visual classification. We describe the process used to select which of these two different methods is most appropriate for each LoTSS source. The final LoTSS-DR1-IDs value-added catalogue presented contains 318 520 radio sources, of which 231 716 (73%) have optical and/or IR identifications in Pan-STARRS and WISE.
Key words: surveys / catalogues / radio continuum: general
The value-added catalogue is available online at https://lofar-surveys.org/, as part of this data release.
The catalogue is available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (22.214.171.124) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A1
© ESO 2019
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