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.

Catalogs

Techniques: image processing

Radio continuum: general

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 B.V

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, Netherlands

K. Duncan

Leiden University

M. Haverkorn

Radboud University

G. Heald

CSIRO Astronomy and Space Science

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, Netherlands

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 Astrofisico de Canarias

G. Gurkan

University of La Laguna

C. Hale

Rhodes University

J. J. Harwood

CSIRO Astronomy and Space Science

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

Uniwersytet Mikołaja Kopernika w Toruniu

S. Mandal

University of Hertfordshire

J. McKean

CSIRO Astronomy and Space Science

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

Uniwersytet Mikołaja Kopernika w Toruniu

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 A1

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201833559

More information

Latest update

7/9/2021 9