NenUFAR: Instrument description and science case

Zarka, Philippe; Tagger, M.; Denis, Loïc; Girard, Julien N.; Konovalenko, A. A.; Atemkeng, Marcellin; Arnaud, M.; Azarian, Sylvain; Barsuglia, M.; Bonafede, A.; Boone, F.; Bosma, Alice; Boyer, Rémy; Branchesi, M.; Briand, Cyril; Cecconi, Baptiste; Celestin, S.; Charrier, Didier; Chassande–Mottin, E.; Coffre, A.; Cognard, I.; Combes, F.; Corbel, S.; Cyril, Courte,; Dabbech, Arwa; Daiboo, S.; Dallier, R.; Dumez-Viou, Cedric; Korso, Mohammed Nabil El; Falgarone, É.; Falkovych, I.; Ferrari, A.; Ferrari, Chiara; Ferrière, K.; Fevotte, C.; Fialkov, Anastasia; Füllekrug, Martin; Gérard, E.; Griebmeier, J.-M.; Guiderdoni, B.; Guillemot, L.; Hessels, J. W. T.; Koopmans, L. V. E.; Kondratiev, V. I.; Lamy, Laurent; Lanz, T.; Larzabal, Pascal; Lehnert, M. D.; Levrier, F.; Loh, Alan; Macario, G.; J, Maintoux,; Martin, L.; Mary, David; Masson, S.; Miville-Deschênes, M.-A.; Oberoi, D.; Panchenko, M.; Pandey-Pommier, M.; Petiteau, Antoine; Pinçon, Jean-Louis; Revenu, B.; Rible, F.; Richard, Cédric; Rücker, H. O.; Salomé, P.; Semelin, B.; Serylak, M.; Smirnov, O.; Stappers, B. W.; Taffoureau, C.; Tasse, C.; Theureau, G.; Tokarsky, P. L.; Torchinsky, S.; Ulyanov, O. M.; Driel, W. van; Vasylieva, I. Y.; Vaubaillon, Jérémie; Vazza, Franco; Vergani, S. D.; Was, M.; Weber, Rodolphe; Захаренко, В. В.

doi:10.1109/icatt.2015.7136773

Cited by 26 publications

(15 citation statements)

References 7 publications

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“…After the LOFAR superterp observing air showers with a few 100 antennas, the next step in precision could be done by the LOFAR extension NenuFAR consisting of almost 2, 000 antennas [225], if a larger fraction of these antennas would be used for air-shower detection in addition to astronomical observations. Just a few years later, the low-frequency instrument of the SKA will be built.…”

Section: Ultra-high Precision For Air Showers Around 100 Pevmentioning

confidence: 99%

“…Moreover, a prototype low-frequency setup named EXTASIS (extinction of airshower induced signal) [224] has been installed to search for radiation emitted by the termination of the air shower when entering the ground [154]. In the future, NenuFAR (new extension in Nançay upgrading LOFAR) will be installed at the CODALEMA site consisting of 1824 dual-polarized antennas operating in the band of 10 − 85 MHz [225]. This will increase the performance of LOFAR for astronomical observations and also for cosmic-ray detection, since a small fraction of the NenuFAR antennas will be equipped with buffers enabling air-shower measurements.…”

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confidence: 99%

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Radio detection of cosmic-ray air showers and high-energy neutrinos

Schröder

2017

Progress in Particle and Nuclear Physics

176

129

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In the last fifteen years radio detection made it back to the list of promising techniques for extensive air showers, firstly, due to the installation and successful operation of digital radio experiments and, secondly, due to the quantitative understanding of the radio emission from atmospheric particle cascades. The radio technique has an energy threshold of about 100 PeV, which coincides with the energy at which a transition from the highest-energy galactic sources to the even more energetic extragalactic cosmic rays is assumed. Thus, radio detectors are particularly useful to study the highest-energy galactic particles and ultra-high-energy extragalactic particles of all types. Recent measurements by various antenna arrays like LOPES, CODALEMA, AERA, LOFAR, Tunka-Rex, and others have shown that radio measurements can compete in precision with other established techniques, in particular for the arrival direction, the energy, and the position of the shower maximum, which is one of the best estimators for the composition of the primary cosmic rays. The scientific potential of the radio technique seems to be maximum in combination with particle detectors, because this combination of complementary detectors can significantly increase the total accuracy for air-shower measurements. This increase in accuracy is crucial for a better separation of different primary particles, like gamma-ray photons, neutrinos, or different types of nuclei, because showers initiated by these particles differ in average depth of the shower maximum and in the ratio between the amplitude of the radio signal and the number of muons. In addition to air-shower measurements, the radio technique can be used to measure particle cascades in dense media, which is a promising technique for detection of ultra-high-energy neutrinos. Several pioneering experiments like ARA, ARIANNA, and ANITA are currently searching for the radio emission by neutrino-induced particle cascades in ice. In the next years these two sub-fields of radio detection of cascades in air and in dense media will likely merge, because several future projects aim at the simultaneous detection of both, high-energy cosmic-rays and neutrinos. SKA will search for neutrino and cosmic-ray initiated cascades in the lunar regolith and simultaneously provide unprecedented detail for air-shower measurements. Moreover, detectors with huge exposure like GRAND, SWORD or EVA are being considered to study the highest energy cosmic rays and neutrinos. This review provides an introduction to the physics of radio emission by particle cascades, an overview on the various experiments and their instrumental properties, and a summary of methods for reconstructing the most important air-shower properties from radio measurements. Finally, potential applications of the radio technique in high-energy astroparticle physics are discussed.

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Section: Ultra-high Precision For Air Showers Around 100 Pevmentioning

confidence: 99%

mentioning

confidence: 99%

Radio detection of cosmic-ray air showers and high-energy neutrinos

Schröder

2017

Progress in Particle and Nuclear Physics

176

129

View full text Add to dashboard Cite

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“…With a resolution and sensitivity greater than any previous systems in the low observing frequencies, the low frequency array (LOFAR) and the square kilometre array (SKA) impose major challenges in terms of telescope design and data processing [1][2][3]. Among these challenges, the calibration step is crucial for the advanced phased array radio telescopes due to the large number of receivers and their wide field-of-view.…”

Section: Introductionmentioning

confidence: 99%

Robust Calibration of Radio Interferometers in Multi-Frequency Scenario

Ollier

Korso

Ferrari

et al. 2018

2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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This paper investigates calibration of sensor arrays in the radio astronomy context. Current and future radio telescopes require computationally efficient algorithms to overcome the new technical challenges as large collecting area, wide field of view and huge data volume. Specifically, we study the calibration of radio interferometry stations with significant direction dependent distortions. We propose an iterative robust calibration algorithm based on a relaxed maximum likelihood estimator for a specific context: i) observations are affected by the presence of outliers and ii) parameters of interest have a specific structure depending on frequency. Variation of parameters across frequency is addressed through a distributed procedure, which is consistent with the new radio synthesis arrays where the full observing bandwidth is divided into multiple frequency channels. Numerical simulations reveal that the proposed robust distributed calibration estimator outperforms the conventional non-robust algorithm and/or the mono-frequency case.

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“…significant in observations with new instruments, we focus in this paper on the regime where the receiving elements of the array have a large field-of-view and possibly long baselines, resulting in a direction dependent calibration problem in which receptors see different parts of the ionosphere [2]. We call this the direction dependent distortion regime.On the one hand, multi-frequency calibration aims to take into account a whole frequency range, e.g., between 30 and 240 MHz for the nominal operating bandpass of the Low Frequency Array (LOFAR) [8,9]. A computationally efficient way to handle the multiple sub-frequency bands in radio astronomy is to apply distributed and consensus algorithms with a decentralized strategy.…”

mentioning

confidence: 99%

“…On the one hand, multi-frequency calibration aims to take into account a whole frequency range, e.g., between 30 and 240 MHz for the nominal operating bandpass of the Low Frequency Array (LOFAR) [8,9]. A computationally efficient way to handle the multiple sub-frequency bands in radio astronomy is to apply distributed and consensus algorithms with a decentralized strategy.…”

mentioning

confidence: 99%

Robust distributed calibration of radio interferometers with direction dependent distortions

et al. 2018

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In radio astronomy, accurate calibration is of crucial importance for the new generation of radio interferometers. More specifically, because of the potential presence of outliers which affect the measured data, robustness needs to be ensured. On the other hand, calibration is improved by taking advantage of these new instruments and exploiting the known structure of parameters of interest across frequency. Therefore, we propose in this paper an iterative robust multi-frequency calibration algorithm based on a distributed and consensus optimization scheme which aims to estimate the complex gains of the receivers and the directional perturbations caused by the ionosphere. Numerical simulations reveal that the proposed distributed calibration technique outperforms the conventional non-robust algorithm and per-channel calibration. significant in observations with new instruments, we focus in this paper on the regime where the receiving elements of the array have a large field-of-view and possibly long baselines, resulting in a direction dependent calibration problem in which receptors see different parts of the ionosphere [2]. We call this the direction dependent distortion regime.On the one hand, multi-frequency calibration aims to take into account a whole frequency range, e.g., between 30 and 240 MHz for the nominal operating bandpass of the Low Frequency Array (LOFAR) [8,9]. A computationally efficient way to handle the multiple sub-frequency bands in radio astronomy is to apply distributed and consensus algorithms with a decentralized strategy. In this context, we apply the Alternating Direction Method of Multipliers (ADMM) [10,6], which is well-suited for large-scale problems as in radio interferometry. This technique is based on decomposition and coordination tasks with a group of computational agents. Each of them has access to a part of the data and finds a solution to a local subproblem, in a restricted frequency interval. Communication with a fusion center enforces consensus among all agents, the goal being to solve a global constrained optimization problem. By collecting and storing data in a distributed way among different computational agents, the global operational cost in the network is substantially reduced.On the other hand, measurements are frequently affected by the presence of outliers due to interference or weak background sources. As a consequence, the noise can no longer be considered Gaussian as in [6].In order to propose an alternative to [11], where the noise model is based on the Student's t distribution, in this work, we make use of a compound-Gaussian model which includes heavy-tailed distributions [12]. This is more general and reveals to be more robust [13]. Therefore, to take into account the presence of outliers and the variability of parameters across frequency, we propose here a Multi-frequency Robust Calibration Algorithm (MRCA) based on a compound-Gaussian distribution for modeling the noise and the consensus ADMM approach [10]. As in [14], we aim at estimating physical paramete...

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NenUFAR: Instrument description and science case

Cited by 26 publications

References 7 publications

Radio detection of cosmic-ray air showers and high-energy neutrinos

Radio detection of cosmic-ray air showers and high-energy neutrinos

Robust Calibration of Radio Interferometers in Multi-Frequency Scenario

Robust distributed calibration of radio interferometers with direction dependent distortions

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