Measuring a Cherenkov ring in the radio emission from air showers at 110–190MHz with LOFAR

Nelles, A.; Schellart, P.; Buitink, S.; Corstanje, A.; Vries, Krijn de; Enriquez, J. E.; Falcke, H.; Frieswijk, W.; Hörandel, J. R.; Scholten, Olaf; Veen, S. ter; Thoudam, Satyendra; Akker, M. van den; Anderson, J. M.; Asgekar, A.; Bell, M. E.; Bentum, Marinus Jan; Bernardi, G.; Best, P. N.; Bregman, J. D.; Breitling, F.; Broderick, J. W.; Brouw, W. N.; Brüggen, M.; Butcher, H. R.; Ciardi, B.; Deller, Adam T.; Duscha, S.; Eislöffel, J.; Fallows, R. A.; Garrett, M. A.; Gunst, A. W.; Hassall, T. E.; Heald, G.; Horneffer, A.; Iacobelli, M.; Juette, E.; Karastergiou, A.; Kondratiev, V. I.; Krämer, M.; Kuniyoshi, M.; Küper, G.; Maat, P.; Mann, G.; Mevius, M.; Norden, M. J.; Paas, H.; Pandey-Pommier, M.; Pietka, G.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H. J. A.; Scaife, A.; Schwarz, Dominik J.; Smirnov, O.; Stappers, B. W.; Steinmetz, Matthias; Stewart, A.; Tagger, M.; Tang, Y.; Tasse, C.; Vermeulen, R. C.; Vocks, C.; Weeren, R. J. van; Wijnholds, Stefan J.; Wucknitz, O.; Yatawatta, S.; Zarka, Philippe

doi:10.1016/j.astropartphys.2014.11.006

Cited by 71 publications

(58 citation statements)

References 24 publications

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“…LOFAR consists of an array of two types of antennas: the low-band antennas (LBA) sensitive to frequencies in a bandwidth of 10 − 90 MHz, and the high-band antennas (HBA) operating in the 110 − 240 MHz range. While air showers have been measured in both frequency ranges [16,17], this study only uses data gathered with the 10 − 90 MHz low-band antennas. A combination of analog and digital filters limits the effective bandwidth to 30 − 80 MHz which has the least amount of radio frequency interference.…”

Section: East [Meters]mentioning

confidence: 99%

The shape of the radio wavefront of extensive air showers as measured with LOFAR

Corstanje

Schellart

Nelles

et al. 2015

Astroparticle Physics

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Extensive air showers, induced by high energy cosmic rays impinging on the Earth's atmosphere, produce radio emission that is measured with the LOFAR radio telescope. As the emission comes from a finite distance of a few kilometers, the incident wavefront is non-planar. A spherical, conical or hyperbolic shape of the wavefront has been proposed, but measurements of individual air showers have been inconclusive so far. For a selected high-quality sample of 161 measured extensive air showers, we have reconstructed the wavefront by measuring pulse arrival times to sub-nanosecond precision in 200 to 350 individual antennas. For each measured air shower, we have fitted a conical, spherical, and hyperboloid shape to the arrival times. The fit quality and a likelihood analysis show that a hyperboloid is the best parametrization. Using a non-planar wavefront shape gives an improved angular resolution, when reconstructing the shower arrival direction. Furthermore, a dependence of the wavefront shape on the shower geometry can be seen. This suggests that it will be possible to use a wavefront shape analysis to get an additional handle on the atmospheric depth of the shower maximum, which is sensitive to the mass of the primary particle.

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Section: East [Meters]mentioning

confidence: 99%

The shape of the radio wavefront of extensive air showers as measured with LOFAR

Corstanje

Schellart

Nelles

et al. 2015

Astroparticle Physics

Self Cite

View full text Add to dashboard Cite

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“…(3). It is expected to hold qualitatively for higher frequencies, above 100 MHz, as for these frequencies, a clear Cherenkov ring is observed both in simulations and in LOFAR data [12]. …”

Section: Methodsmentioning

confidence: 94%

The influence of the atmospheric refractive index on radioX_maxmeasurements of air showers

et al. 2017

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Abstract. The refractive index of the atmosphere, which is n ≈ 1.0003 at sea level, varies with altitude and with local temperature, pressure and humidity. When performing radio measurements of air showers, natural variations in n will change the radio lateral intensity distribution, by changing the Cherenkov angle. Using CoREAS simulations, we have evaluated the systematic error on measurements of the shower maximum X max due to variations in n. It was found that a 10 % increase in refractivity (n − 1) leads to an underestimation of X max between 8 and 22 g/cm 2 for proton-induced showers at zenith angles from 15 to 45 degrees, respectively.

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“…This project is collecting data and can detect the composition of the primary particle [20]. The first results have been published in several journals [21,22,23,24] and are also presented at this conference.…”

Section: Pos(icrc2015)684mentioning

confidence: 99%

NuMoon: Status of ultra high energy particle searches with LOFAR

Veen¹,

Buitink²,

Corstanje³

et al. 2016

Proceedings of the 34th International Cosmic Ray Conference — PoS(ICRC2015)

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The lunar Askaryan technique is one of the few ways to obtain a large enough collecting area to detect ultra high energy cosmic rays and neutrinos at the highest end of the known spectrum, above 10 21 eV. The flux of these particles is unknown, but if they are found they either point back to the best cosmic accelerators or they can be the products of the decay of exotic particles such as cosmic strings. Using the lunar Askaryan technique means searching for radio signals created by a particle shower that is induced when an ultra high energy particle collides with the Moon. The large collecting area that the Moon offers can especially be used at frequencies between 100-200 MHz, where the radiation is spread out over a wider angle and thus more of the lunar surface can be used for a possible detection. The NuMoon project therefore observes the Moon at these frequencies to search for nanosecond pulses. A first project with the Westerbork Synthesis Radio Telescope has placed the most stringent upper limits on the flux of ultra high energy cosmic rays and neutrinos. The next step is to observe with LOFAR, currently one of the most sensitive low frequency telescopes. In this contribution I will present the status and plans of the project.

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Measuring a Cherenkov ring in the radio emission from air showers at 110–190MHz with LOFAR

Cited by 71 publications

References 24 publications

The shape of the radio wavefront of extensive air showers as measured with LOFAR

The shape of the radio wavefront of extensive air showers as measured with LOFAR

The influence of the atmospheric refractive index on radioX_maxmeasurements of air showers

NuMoon: Status of ultra high energy particle searches with LOFAR

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Measuring a Cherenkov ring in the radio emission from air showers at 110–190MHz with LOFAR

Cited by 71 publications

References 24 publications

The shape of the radio wavefront of extensive air showers as measured with LOFAR

The shape of the radio wavefront of extensive air showers as measured with LOFAR

The influence of the atmospheric refractive index on radioXmaxmeasurements of air showers

NuMoon: Status of ultra high energy particle searches with LOFAR

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Product

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The influence of the atmospheric refractive index on radioX_maxmeasurements of air showers