LOFAR: The LOw-Frequency ARray

M. P. van Haarlem (1) , M. W. Wise (1, 2) , A. W. Gunst (1) , G. Heald (1) , J. P. Mckean (1) , J. W. T. Hessels (3) , A. G. de Bruyn (1) , R. Nijboer , J. Swinbank (2) , R. Fallows (4) , M. Brentjens (1) , A. Nelles (5) , R. Beck (6) , H. Falcke (5, 7, 1) , R. Fender (8) , J. Hörandel , L. V. E. Koopmans , G. Mann (9) , G. Miley , H. Röttgering (10) , B. W. Stappers (11) , R. A. M. J. Wijers (2) , S. Zaroubi , M. van Den Akker , A. Alexov (1) , J. Anderson (12) , K. Anderson , A. van Ardenne , M. Arts (13) , A. Asgekar (1) , I. M. Avruch (14) , F. Batejat (12) , L. Bähren (2) , M. E. Bell (8) , M. R. Bell (8) , I. van Bemmel , P. Bennema , M. J. Bentum (1) , G. Bernardi , P. Best (15) , L. Bîrzan , A. Bonafede (16) , A. -J. Boonstra (1) , R. Braun (17) , J. Bregman (1) , F. Breitling (9) , R. H. van de Brink , J. Broderick (8) , P. C. Broekema , W. N. Brouw (18) , M. Brüggen (16) , H. R. Butcher (1) , W. van Cappellen (19) , B. Ciardi (12) , T. Coenen (1) , J. Conway , A. Coolen (20) , A. Corstanje , S. Damstra , O. Davies , A. T. Deller , R. -J. Dettmar , G. van Diepen , K. Dijkstra (21) , P. Donker , A. Doorduin , J. Dromer , M. Drost , A. van Duin , J. Eislöffel (22) , J. van Enst , C. Ferrari (23) , W. Frieswijk , H. Gankema , M. A. Garrett (10, 1) , F. de Gasperin , M. Gerbers (1) , E. de Geus (24) , Jean-Mathias Griessmeier (25) , T. Grit , P. Gruppen , J. P. Hamaker , T. Hassall (11) , M. Hoeft (22) , H. Holties (1) , A. Horneffer , A. van Der Horst , A. van Houwelingen (26) , A. Huijgen , M. Iacobelli (27, 28) , H. Intema , N. Jackson , V. Jelic (29) , A. de Jong (1) , E. Juette (30) , D. Kant , A. Karastergiou (31) , A. Koers (32) , H. Kollen , V. I. Kondratiev (1) , E. Kooistra , Y. Koopman , A. Koster , M. Kuniyoshi (7) , M. Kramer (33) , G. Kuper (1) , P. Lambropoulos (1) , C. Law (2) , J. van Leeuwen (3) , J. Lemaitre , M. Loose (34) , P. Maat (1) , G. Macario , S. Markoff (2) , J. Masters (35) , D. Mckay-Bukowski (36) , H. Meijering , H. Meulman (1) , M. Mevius (1) , E. Middelberg , R. Millenaar , J. C. A. Miller-Jones (2) , R. N. Mohan (37) , J. D. Mol (38) , J. Morawietz , R. Morganti (18, 1) , D. D. Mulcahy , E. Mulder (39) , H. Munk (1) , L. Nieuwenhuis , R. van Nieuwpoort , J. E. Noordam (1) , M. Norden , A. Noutsos (7) , A. R. Offringa , H. Olofsson (40) , A. Omar (1, 41) , E. Orrú , R. Overeem , H. Paas (1) , M. Pandey-Pommier (42) , V. N. Pandey , R. Pizzo (1) , A. Polatidis (1) , D. Rafferty (43) , S. Rawlings , W. Reich (7) , J. -P. de Reijer , J. Reitsma (44) , A. Renting , P. Riemers , E. Rol (2) , J. W. Romein , J. Roosjen , M. Ruiter , A. Scaife (45) , K. van Der Schaaf , B. Scheers (2) , P. Schellart (5) , A. Schoenmakers , G. Schoonderbeek , M. Serylak (25, 46) , A. Shulevski , J. Sluman (1) , O. Smirnov (47) , C. Sobey (7) , H. Spreeuw (2) , M. Steinmetz , C. G. M. Sterks (48) , H. -J. Stiepel , K. Stuurwold , Michel Tagger (25) , Y. Tang (49) , C. Tasse (50) , I. Thomas (51) , S. Thoudam (5) , M. C. Toribio (52) , B. van Der Tol , O. Usov , M. van Veelen , A. -J. van Der Veen (53) , S. ter Veen (54) , J. P. W. Verbiest (7) , R. Vermeulen , N. Vermaas , C. Vocks , C. Vogt , M. de Vos , E. van Der Wal , R. van Weeren (1, 55) , H. Weggemans , P. Weltevrede (11) , S. White , S. J. Wijnholds (1) , T. Wilhelmsson , O. Wucknitz (56) , S. Yatawatta (18) , P. Zarka (50) , A. Zensus , J. van Zwieten

1 ASTRON - Netherlands Institute for Radio Astronomy
2 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
3 UvA - University of Amsterdam [Amsterdam]
4 Institute of Mathematical and Physical Sciences
5 Radboud University [Nijmegen]
6 LCPM - Laboratoire de Chimie Physique Moléculaire
7 MPIFR - Max-Planck-Institut für Radioastronomie
8 University of Southampton
9 AIP - Leibniz-Institut für Astrophysik Potsdam
10 Leiden Observatory [Leiden]
11 Jodrell Bank Centre for Astrophysics
12 Max Planck Institute for Astrophysics
13 Medical Center Haaglanden
14 SRON - SRON Netherlands Institute for Space Research
15 University of Edinburgh
16 Jacobs University [Bremen]
17 TU Dresden - Technische Universität Dresden = Dresden University of Technology
18 Kapteyn Astronomical Institute [Groningen]
19 Department of Reproduction and Development
20 London Institute for Mathematical Sciences
21 Netherlands Centre for Biodiversity, Leiden, The Netherlands
22 TLS - Thüringer Landessternwarte Tautenburg
23 LRGP - Laboratoire Réactions et Génie des Procédés
24 Medstar Research Institute
25 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
26 Plant Research International, Business Unit Bioscience
27 Sapienza University of Rome - Dipartimento di Matematica "Guido Castelnuovo" [Roma I]
28 CMLS - Centre de Mathématiques Laurent Schwartz
29 UMR PVBMT - Peuplements végétaux et bioagresseurs en milieu tropical
30 Ruhr-Universität Bochum [Bochum]
31 Oxford Astrophysics
32 Amsterdam Center for Multiscale Modeling
33 VUMC - Vrije Universiteit Medical Centre
34 Queen's Medical Centre
35 NRAO - National Radio Astronomy Observatory
36 University of Oulu
37 Department of Economics
38 Center for Agricultural Research in Suriname CELOS and Department of Biology
39 DLR Institute of Aerospace Medicine
40 OSO - Onsala Space Observatory
41 GFI / BiU - Geophysical Institute [Bergen]
42 CRAL - Centre de Recherche Astrophysique de Lyon
43 Department of Astronomy and Astrophysics [PennState]
44 AMC - Academic Medical Center - Academisch Medisch Centrum [Amsterdam]
45 School of Physics and Astronomy [Southampton]
46 USN - Unité Scientifique de la Station de Nançay
47 Rhodes University, Grahamstown
48 Center for Information Technology CIT
49 PASTEUR - Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640)
50 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
51 Center for Operations and Econometrics
52 Finca El Encin
53 EINDHOVEN - Surgery - Department of Surgery
54 IMAPP - Institute for Mathematics, Astrophysics and Particle Physics
55 CfA - Harvard-Smithsonian Center for Astrophysics
56 AlfA - Argelander-Institut für Astronomie

LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing capabilities. Spreading out from a core located near the village of Exloo in the northeast of the Netherlands, a total of 40 LOFAR stations are nearing completion. A further five stations have been deployed throughout Germany, and one station has been built in each of France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR achieves unparalleled sensitivity and angular resolution in the low-frequency radio regime. The LOFAR facilities are jointly operated by the International LOFAR Telescope (ILT) foundation, as an observatory open to the global astronomical community. LOFAR is one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. LOFAR's new capabilities, techniques and modus operandi make it an important pathfinder for the Square Kilometre Array (SKA). We give an overview of the LOFAR instrument, its major hardware and software components, and the core science objectives that have driven its design. In addition, we present a selection of new results from the commissioning phase of this new radio observatory.

Keywords: radio lines: general; radio continuum: general; telescopes; reionization; instrumentation: interferometers -radio continuum: general -radio lines: general -dark ages; instrumentation: interferometers; first stars - telescopes

Domains: Sciences of the Universe [physics]

M. P. van Haarlem, M. W. Wise, A. W. Gunst, G. Heald, J. P. Mckean, et al.. LOFAR: The LOw-Frequency ARray. Astronomy and Astrophysics - A&A, 2013, A2, 53 p. ⟨10.1051/0004-6361/201220873⟩. ⟨insu-01288431⟩