LOFAR: The LOw-Frequency ARray

By M. V. Haarlem, M. Wise, A. Gunst, G. Heald, J. McKean, Jason W. T. Hessels, A. Bruyn, R. Nijboer, J. Swinbank, R. Fallows and 190 more. 2013

1,928 citations recorded by the source corpus.

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.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/14e1dbec20611a4a494371906c3c2be9577aed5b

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Citations in the corpus

Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, background): “…interferometer experiments aiming to detect the power spectrum of the signal include the Murchison Wide Field Array (MWA4; Bowman et al. 2013; Tingay et al. 2013), Low Frequency Array (LOFAR5; van Haarlem et al. 2013), Precision Array for Probing Epoch of Reionisation (PAPER6; Parsons et al. 2010).”
COSMIC REIONIZATION AND EARLY STAR-FORMING GALAXIES: A JOINT ANALYSIS OF NEW CONSTRAINTS FROM PLANCK AND THE HUBBLE SPACE TELESCOPE (2015, background): “Our results offer extra hope for efforts to make redshifted 21-cm measurements of neutral hydrogen in the IGM, as the experimental foregrounds are weakest at low redshifts (e.g., van Haarlem et al. 2013; Bowman et al. 2013; Pober et al. 2014).”
wsclean: an implementation of a fast, generic wide-field imager for radio astronomy (2014, background): “Examples of such telescopes include the Murchison Widefield Array (MWA, Lonsdale et al. 2009, Tingay et al. 2013), the upgraded Jansky Very Large Array (JVLA) and the Low-Frequency Array (LOFAR, Van Haarlem et al. 2013).”
Detecting cosmic rays with the LOFAR radio telescope (2013, background): “These tables are generated by phase-calibrating on the strongest astronomical radio sources and are regularly tested and updated if necessary (van Haarlem et al. 2013).”
GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue (2016, background): “These instruments include the Low Frequency Array (LOFAR; van Haarlem et al. 2013), the Precision Array for Probing the Epoch of Reionization (PAPER; Parsons et al. 2010), the Long Wavelength Array (LWA; Ellingson et al. 2013), and the Murchison Widefield Array (MWA; Lonsdale et al. 2009; Tingay et…”
WHAT NEXT-GENERATION 21 cm POWER SPECTRUM MEASUREMENTS CAN TEACH US ABOUT THE EPOCH OF REIONIZATION (2013, methodology): “Although this model is ∼ 100 K lower than the system measured by Parsons et al. (2013), it is consistent with recent LOFAR measurements (Yatawatta et al. 2013; van Haarlem et al. 2013).”
The Upgraded GMRT:Opening New Windows on the Radio Universe (2017, background): “4, 25 AUGUST 2017 708 system; (6) Sophisticated, next-generation monitor and control system; (7) Matching improvements in mechanical systems, electrical and civil infrastructure and computing resources; (8) Implementation of the upgrade with minimal disruption to the availability of the existing GMR”
The International Pulsar Timing Array: First Data Release (2016, background): “These are the European LOw-Frequency ARray (LOFAR; Stappers et al. 2011; van Haarlem et al. 2013), the Long-Wavelength Array (LWA) in New Mexico (Dowell et al. 2013) and the Murchison Widefield Array (MWA; Bhat et al. 2014) in Western Australia.”
21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal (2015, methodology): “LOFAR: we model LOFAR using the antennas positions listed in van Haarlem et al. (2013).”
Multi-messenger observations of a binary neutron star merger (2017, background): “…ATCA, Effelsberg-100 m (Barr et al. 2013), the Giant Metrewave Radio Telescope (GMRT; Swarup et al. 1991), the Low-Frequency Array (LOFAR; van Haarlem et al. 2013), the Long Wavelength Array (LWA1), MeerKAT (Goedhart et al. 2017a), the Murchison Widefield Array (MWA; Tingay et al. 2013),…”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, background): “LOFAR has a wide field-of-view (about 10° between nulls at 140 MHz, van Haarlem et al. 2013) and the visibilities are susceptible to direction-dependent gain variations mainly due to time varying primary beam and ionospheric effects.”
THE ELEVENTH AND TWELFTH DATA RELEASES OF THE SLOAN DIGITAL SKY SURVEY: FINAL DATA FROM SDSS-III (2015, background): “SDSS-III Observations of LOFAR Sources: This ancillary program was intended to target radio sources identified in deep observations of the ELAIS-N1 region by the Low Frequency Array (LOFAR; van Haarlem et al. 2013).”
PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM AT z = 8.4 (2015, methodology): “Examples of such interferometers targeting the reionization signal include the GMRT (Paciga et al. 2013), LOFAR (van Haarlem et al. 2013), the MWA (Tingay et al. 2013), the 21CMA (Peterson et al. 2004; Wu 2009), and the Donald C. Backer Precision Array for Probe the Epoch of Reionization (PAPER;…”