The LOFAR Two-metre Sky Survey: II. First data release
Review article, 2019
The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168 MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. For this data release 424 square degrees, or 2% of the eventual coverage, in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45°00′00″ to 57°00′00″) were mapped using a fully automated direction-dependent calibration and imaging pipeline that we developed. A total of 325 694 sources are detected with a signal of at least five times the noise, and the source density is a factor of ∼10 higher than the most sensitive existing very wide-area radio-continuum surveys. The median sensitivity is S144 MHz = 71 μJy beam -1 and the point-source completeness is 90% at an integrated flux density of 0.45 mJy. The resolution of the images is 6″ and the positional accuracy is within 0.2″. This data release consists of a catalogue containing location, flux, and shape estimates together with 58 mosaic images that cover the catalogued area. In this paper we provide an overview of the data release with a focus on the processing of the LOFAR data and the characteristics of the resulting images. In two accompanying papers we provide the radio source associations and deblending and, where possible, the optical identifications of the radio sources together with the photometric redshifts and properties of the host galaxies. These data release papers are published together with a further ∼20 articles that highlight the scientific potential of LoTSS.
Radio continuum: general
Catalogs
Techniques: image processing
Surveys
Author
T. W. Shimwell
Netherlands Institute for Radio Astronomy (ASTRON)
C. Tasse
Observatoire de Paris-Meudon
M. J. Hardcastle
University of Hertfordshire
A. P. Mechev
Leiden University
W. L. Williams
University of Hertfordshire
P.N. Best
Royal Observatory
H. Rottgering
Leiden University
J. R. Callingham
Netherlands Institute for Radio Astronomy (ASTRON)
T. J. Dijkema
Netherlands Institute for Radio Astronomy (ASTRON)
F. De Gasperin
Leiden University
D. N. Hoang
Leiden University
B. Hugo
Rhodes University
M. Mirmont
Ampyx Power
J. B. R. Oonk
Netherlands Institute for Radio Astronomy (ASTRON)
I. Prandoni
Istituto di Radioastronomia
D. Rafferty
University of Hamburg
J. Sabater
Royal Observatory
O. Smirnov
Rhodes University
R. van Weeren
Leiden University
G. White
Open University
M. Atemkeng
Rhodes University
L. Bester
Rhodes University
E. Bonnassieux
Square Kilometre Array, South Africa
M. Brueggen
University of Hamburg
G. Brunetti
Istituto di Radioastronomia
K. T. Chy
Jagiellonian University in Kraków
R. Cochrane
Royal Observatory
John Conway
Chalmers, Space, Earth and Environment, Onsala Space Observatory
J. H. Croston
Open University
A. Danezi
Surfsara Bv
K. Duncan
Leiden University
M. Haverkorn
Radboud University
G. Heald
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
M. Iacobelli
Netherlands Institute for Radio Astronomy (ASTRON)
H. T. Intema
Leiden University
N. Jackson
University of Manchester
M. Jamrozy
Jagiellonian University in Kraków
M.J. Jarvis
University of Oxford
R. Lakhoo
University of Oxford
M. Mevius
Netherlands Institute for Radio Astronomy (ASTRON)
G. Miley
Leiden University
L. Morabito
University of Oxford
R. Morganti
Netherlands Institute for Radio Astronomy (ASTRON)
D. Nisbet
Royal Observatory
E. Orrú
Netherlands Institute for Radio Astronomy (ASTRON)
S. Perkins
Square Kilometre Array, South Africa
R. Pizzo
Surfsara Bv
C. Schrijvers
University of Hertfordshire
D. J.B. Smith
Netherlands Institute for Radio Astronomy (ASTRON)
R. Vermeulen
Netherlands Institute for Radio Astronomy (ASTRON)
M. W. Wise
Royal Observatory
L. Alegre
University of Portsmouth
D.J. Bacon
Joint Institute for VLBI in Europe (JIVE)
I. van Bemmel
University of Manchester
R. J. Beswick
University of Hamburg
A. Bonafede
Istituto di Radioastronomia
A. Botteon
S. Bourke
Netherlands Institute for Radio Astronomy (ASTRON)
M. Brienza
Leiden University
G. Calistro Rivera
Istituto di Radioastronomia
R. Cassano
University of Manchester
A. O. Clarke
University of Nottingham
C. Conselice
Ruhr-Universität Bochum
R. J. Dettmar
Thüringer Landessternwarte Tautenburg
A. Drabent
Thüringer Landessternwarte Tautenburg
C. Dumba
Thüringer Landessternwarte Tautenburg
K.L. Emig
Leiden University
T.A. Enßlin
Max Planck Society
C. Ferrari
Observatoire de la Cote d'Azur
M. A. Garrett
University of Manchester
R.T. Génova-Santos
Leiden University
A. Goyal
Instituto de Astrofísica de Canarias
G. Gurkan
University of La Laguna
C. Hale
Rhodes University
J. J. Harwood
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
V. Heesen
University of Oxford
M. Hoeft
University of Hertfordshire
Cathy Horellou
University of Hamburg
C. Jackson
Thüringer Landessternwarte Tautenburg
G. Kokotanekov
R. Kondapally
Netherlands Institute for Radio Astronomy (ASTRON)
M. Kunert-Bajraszewska
University of Amsterdam
V. Mahatma
Royal Observatory
E. Mahony
Nicolaus Copernicus University
S. Mandal
University of Hertfordshire
J. McKean
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
A. Merloni
Max Planck Society
B. Mingo
LESIA - Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique
A. Miskolczi
Ruhr-Universität Bochum
S. Mooney
Max Planck Society
B. Nikiel-Wroczyński
University College Dublin
Shane P. O'Sullivan
Jagiellonian University in Kraków
J. Quinn
University of Hamburg
W. Reich
University College Dublin
C. Roskowiński
Max Planck Society
A. Rowlinson
Nicolaus Copernicus University
F. Savini
University of Hamburg
A. Saxena
Leiden University
D. J. Schwarz
Bielefeld University
A. Shulevski
Netherlands Institute for Radio Astronomy (ASTRON)
S. S. Sridhar
Netherlands Institute for Radio Astronomy (ASTRON)
H.R. Stacey
Netherlands Institute for Radio Astronomy (ASTRON)
S. Urquhart
Open University
M. H. D. van der Wiel
Netherlands Institute for Radio Astronomy (ASTRON)
Eskil Varenius
Chalmers, Space, Earth and Environment, Onsala Space Observatory
B. Webster
Open University
A. Wilber
University of Hamburg
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 622 A1Subject Categories
Astronomy, Astrophysics and Cosmology
DOI
10.1051/0004-6361/201833559