Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE

A. Nigl; W. D. Apel; J. C. Arteaga; T. Asch; J. Auffenberg; F. Badea; L. Bähren; K. Bekk; M. Bertaina; P. L. Biermann; J. Blümer; H. Bozdog; I. M. Brancus; M. Brüggemann; P. Buchholz; S. Buitink; H. Butcher; E. Cantoni; A. Chiavassa; F. Cossavella; K. Daumiller; V. De Souza; F. Di Pierro; P. Doll; R. Engel; H. Falcke; H. Gemmeke; P. L. Ghia; R. Glasstetter; C. Grupen; A. Haungs; D. Heck; J. R. Hörandel; A. Horneffer; T. Huege; P. G. Isar; K. H. Kampert; D. Kickelbick; Y. Kolotaev; O. Krömer; J. Kuijpers; S. Lafebre; P. Łuczak; M. Manewald; H. J. Mathes; H. J. Mayer; C. Meurer; B. Mitrica; C. Morello; G. Navarra; S. Nehls; J. Oehlschläger; S. Ostapchenko; S. Over; M. Petcu; T. Pierog; J. Rautenberg; H. Rebel; M. Roth; A. Saftoiu; H. Schieler; A. Schmidt; F. Schröder; O. Sima; K. Singh; M. Stümpert; G. Toma; G. C. Trinchero; H. Ulrich; J. Van Buren; W. Walkowiak; A. Weindl; J. Wochele; J. Zabierowski; J. A. Zensus

doi:10.1051/0004-6361:20079218

Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE

A. Nigl^*, W. D. Apel, J. C. Arteaga, T. Asch, J. Auffenberg, F. Badea, L. Bähren, K. Bekk, M. Bertaina, P. L. Biermann, J. Blümer, H. Bozdog, I. M. Brancus, M. Brüggemann, P. Buchholz, S. Buitink, H. Butcher, E. Cantoni, A. Chiavassa, F. CossavellaK. Daumiller, V. De Souza, F. Di Pierro, P. Doll, R. Engel, H. Falcke, H. Gemmeke, P. L. Ghia, R. Glasstetter, C. Grupen, A. Haungs, D. Heck, J. R. Hörandel, A. Horneffer, T. Huege, P. G. Isar, K. H. Kampert, D. Kickelbick, Y. Kolotaev, O. Krömer, J. Kuijpers, S. Lafebre, P. Łuczak, M. Manewald, H. J. Mathes, H. J. Mayer, C. Meurer, B. Mitrica, C. Morello, G. Navarra, S. Nehls, J. Oehlschläger, S. Ostapchenko, S. Over, M. Petcu, T. Pierog, J. Rautenberg, H. Rebel, M. Roth, A. Saftoiu, H. Schieler, A. Schmidt, F. Schröder, O. Sima, K. Singh, M. Stümpert, G. Toma, G. C. Trinchero, H. Ulrich, J. Van Buren, W. Walkowiak, A. Weindl, J. Wochele, J. Zabierowski, J. A. Zensus

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

29 Citations (Scopus)

Abstract

Aims. We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods. We produce 4D radio images on time-scales of nanoseconds using digital beam-forming. Each pixel of the image is calculated for three spatial dimensions and as a function of time. The third spatial dimension is obtained by calculating the beam focus for a range of curvature radii fitted to the signal wave front. We search this multi-dimensional parameter space for the direction of maximum coherence of the air shower radio signal and compare it to the direction provided by KASCADE. Results. The maximum radio emission of air showers is obtained for curvature radii being larger than 3 km. We find that the direction of the emission maximum can change when optimizing the curvature radius. This dependence dominates the statistical uncertainty for the direction determination with LOPES. Furthermore, we find a tentative increase of the curvature radius to lower elevations, where the air showers pass through a larger atmospheric depth. The distribution of the offsets between the directions of both experiments is found to decrease linearly with increasing signal-to-noise ratio. Significantly increased offsets and enhanced signal strengths are found in events which were modified by strong electric fields in thunderstorm clouds. Conclusions. We conclude that the angular resolution of LOPES is sufficient to determine the direction which maximizes the observed electric field amplitude. However, the statistical uncertainty of the directions is not determined by the resolution of LOPES, but by the uncertainty of the curvature radius. We do not find any systematic deviation between the directions determined from the radio signal and from the detected particles. This result places a strong supportive argument for the use of the radio technique to study the origin of high-energy cosmic rays.

Original language	English
Pages (from-to)	781-788
Number of pages	8
Journal	Astronomy and Astrophysics
Volume	487
Issue number	2
DOIs	https://doi.org/10.1051/0004-6361:20079218
Publication status	Published - Aug 2008
Externally published	Yes

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10.1051/0004-6361:20079218

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Nigl, A., Apel, W. D., Arteaga, J. C., Asch, T., Auffenberg, J., Badea, F., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Brüggemann, M., Buchholz, P., Buitink, S., Butcher, H., Cantoni, E., Chiavassa, A., ... Zensus, J. A. (2008). Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE. Astronomy and Astrophysics, 487(2), 781-788. https://doi.org/10.1051/0004-6361:20079218

@article{992157a3ea6e4aa9acb1dd0dbd376f2c,

title = "Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE",

abstract = "Aims. We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods. We produce 4D radio images on time-scales of nanoseconds using digital beam-forming. Each pixel of the image is calculated for three spatial dimensions and as a function of time. The third spatial dimension is obtained by calculating the beam focus for a range of curvature radii fitted to the signal wave front. We search this multi-dimensional parameter space for the direction of maximum coherence of the air shower radio signal and compare it to the direction provided by KASCADE. Results. The maximum radio emission of air showers is obtained for curvature radii being larger than 3 km. We find that the direction of the emission maximum can change when optimizing the curvature radius. This dependence dominates the statistical uncertainty for the direction determination with LOPES. Furthermore, we find a tentative increase of the curvature radius to lower elevations, where the air showers pass through a larger atmospheric depth. The distribution of the offsets between the directions of both experiments is found to decrease linearly with increasing signal-to-noise ratio. Significantly increased offsets and enhanced signal strengths are found in events which were modified by strong electric fields in thunderstorm clouds. Conclusions. We conclude that the angular resolution of LOPES is sufficient to determine the direction which maximizes the observed electric field amplitude. However, the statistical uncertainty of the directions is not determined by the resolution of LOPES, but by the uncertainty of the curvature radius. We do not find any systematic deviation between the directions determined from the radio signal and from the detected particles. This result places a strong supportive argument for the use of the radio technique to study the origin of high-energy cosmic rays.",

keywords = "Acceleration of particles, Elementary particles, Instrumentation: detectors, Methods: observational, Radiation mechanisms: non-thermal, Techniques: image processing",

author = "A. Nigl and Apel, {W. D.} and Arteaga, {J. C.} and T. Asch and J. Auffenberg and F. Badea and L. B{\"a}hren and K. Bekk and M. Bertaina and Biermann, {P. L.} and J. Bl{\"u}mer and H. Bozdog and Brancus, {I. M.} and M. Br{\"u}ggemann and P. Buchholz and S. Buitink and H. Butcher and E. Cantoni and A. Chiavassa and F. Cossavella and K. Daumiller and {De Souza}, V. and {Di Pierro}, F. and P. Doll and R. Engel and H. Falcke and H. Gemmeke and Ghia, {P. L.} and R. Glasstetter and C. Grupen and A. Haungs and D. Heck and H{\"o}randel, {J. R.} and A. Horneffer and T. Huege and Isar, {P. G.} and Kampert, {K. H.} and D. Kickelbick and Y. Kolotaev and O. Kr{\"o}mer and J. Kuijpers and S. Lafebre and P. {\L}uczak and M. Manewald and Mathes, {H. J.} and Mayer, {H. J.} and C. Meurer and B. Mitrica and C. Morello and G. Navarra and S. Nehls and J. Oehlschl{\"a}ger and S. Ostapchenko and S. Over and M. Petcu and T. Pierog and J. Rautenberg and H. Rebel and M. Roth and A. Saftoiu and H. Schieler and A. Schmidt and F. Schr{\"o}der and O. Sima and K. Singh and M. St{\"u}mpert and G. Toma and Trinchero, {G. C.} and H. Ulrich and {Van Buren}, J. and W. Walkowiak and A. Weindl and J. Wochele and J. Zabierowski and Zensus, {J. A.}",

year = "2008",

month = aug,

doi = "10.1051/0004-6361:20079218",

language = "English",

volume = "487",

pages = "781--788",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

number = "2",

}

Nigl, A, Apel, WD, Arteaga, JC, Asch, T, Auffenberg, J, Badea, F, Bähren, L, Bekk, K, Bertaina, M, Biermann, PL, Blümer, J, Bozdog, H, Brancus, IM, Brüggemann, M, Buchholz, P, Buitink, S, Butcher, H, Cantoni, E, Chiavassa, A, Cossavella, F, Daumiller, K, De Souza, V, Di Pierro, F, Doll, P, Engel, R, Falcke, H, Gemmeke, H, Ghia, PL, Glasstetter, R, Grupen, C, Haungs, A, Heck, D, Hörandel, JR, Horneffer, A, Huege, T, Isar, PG, Kampert, KH, Kickelbick, D, Kolotaev, Y, Krömer, O, Kuijpers, J, Lafebre, S, Łuczak, P, Manewald, M, Mathes, HJ, Mayer, HJ, Meurer, C, Mitrica, B, Morello, C, Navarra, G, Nehls, S, Oehlschläger, J, Ostapchenko, S, Over, S, Petcu, M, Pierog, T, Rautenberg, J, Rebel, H, Roth, M, Saftoiu, A, Schieler, H, Schmidt, A, Schröder, F, Sima, O, Singh, K, Stümpert, M, Toma, G, Trinchero, GC, Ulrich, H, Van Buren, J, Walkowiak, W, Weindl, A, Wochele, J, Zabierowski, J & Zensus, JA 2008, 'Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE', Astronomy and Astrophysics, vol. 487, no. 2, pp. 781-788. https://doi.org/10.1051/0004-6361:20079218

TY - JOUR

T1 - Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE

AU - Nigl, A.

AU - Apel, W. D.

AU - Arteaga, J. C.

AU - Asch, T.

AU - Auffenberg, J.

AU - Badea, F.

AU - Bähren, L.

AU - Bekk, K.

AU - Bertaina, M.

AU - Biermann, P. L.

AU - Blümer, J.

AU - Bozdog, H.

AU - Brancus, I. M.

AU - Brüggemann, M.

AU - Buchholz, P.

AU - Buitink, S.

AU - Butcher, H.

AU - Cantoni, E.

AU - Chiavassa, A.

AU - Cossavella, F.

AU - Daumiller, K.

AU - De Souza, V.

AU - Di Pierro, F.

AU - Doll, P.

AU - Engel, R.

AU - Falcke, H.

AU - Gemmeke, H.

AU - Ghia, P. L.

AU - Glasstetter, R.

AU - Grupen, C.

AU - Haungs, A.

AU - Heck, D.

AU - Hörandel, J. R.

AU - Horneffer, A.

AU - Huege, T.

AU - Isar, P. G.

AU - Kampert, K. H.

AU - Kickelbick, D.

AU - Kolotaev, Y.

AU - Krömer, O.

AU - Kuijpers, J.

AU - Lafebre, S.

AU - Łuczak, P.

AU - Manewald, M.

AU - Mathes, H. J.

AU - Mayer, H. J.

AU - Meurer, C.

AU - Mitrica, B.

AU - Morello, C.

AU - Navarra, G.

AU - Nehls, S.

AU - Oehlschläger, J.

AU - Ostapchenko, S.

AU - Over, S.

AU - Petcu, M.

AU - Pierog, T.

AU - Rautenberg, J.

AU - Rebel, H.

AU - Roth, M.

AU - Saftoiu, A.

AU - Schieler, H.

AU - Schmidt, A.

AU - Schröder, F.

AU - Sima, O.

AU - Singh, K.

AU - Stümpert, M.

AU - Toma, G.

AU - Trinchero, G. C.

AU - Ulrich, H.

AU - Van Buren, J.

AU - Walkowiak, W.

AU - Weindl, A.

AU - Wochele, J.

AU - Zabierowski, J.

AU - Zensus, J. A.

PY - 2008/8

Y1 - 2008/8

N2 - Aims. We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods. We produce 4D radio images on time-scales of nanoseconds using digital beam-forming. Each pixel of the image is calculated for three spatial dimensions and as a function of time. The third spatial dimension is obtained by calculating the beam focus for a range of curvature radii fitted to the signal wave front. We search this multi-dimensional parameter space for the direction of maximum coherence of the air shower radio signal and compare it to the direction provided by KASCADE. Results. The maximum radio emission of air showers is obtained for curvature radii being larger than 3 km. We find that the direction of the emission maximum can change when optimizing the curvature radius. This dependence dominates the statistical uncertainty for the direction determination with LOPES. Furthermore, we find a tentative increase of the curvature radius to lower elevations, where the air showers pass through a larger atmospheric depth. The distribution of the offsets between the directions of both experiments is found to decrease linearly with increasing signal-to-noise ratio. Significantly increased offsets and enhanced signal strengths are found in events which were modified by strong electric fields in thunderstorm clouds. Conclusions. We conclude that the angular resolution of LOPES is sufficient to determine the direction which maximizes the observed electric field amplitude. However, the statistical uncertainty of the directions is not determined by the resolution of LOPES, but by the uncertainty of the curvature radius. We do not find any systematic deviation between the directions determined from the radio signal and from the detected particles. This result places a strong supportive argument for the use of the radio technique to study the origin of high-energy cosmic rays.

AB - Aims. We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods. We produce 4D radio images on time-scales of nanoseconds using digital beam-forming. Each pixel of the image is calculated for three spatial dimensions and as a function of time. The third spatial dimension is obtained by calculating the beam focus for a range of curvature radii fitted to the signal wave front. We search this multi-dimensional parameter space for the direction of maximum coherence of the air shower radio signal and compare it to the direction provided by KASCADE. Results. The maximum radio emission of air showers is obtained for curvature radii being larger than 3 km. We find that the direction of the emission maximum can change when optimizing the curvature radius. This dependence dominates the statistical uncertainty for the direction determination with LOPES. Furthermore, we find a tentative increase of the curvature radius to lower elevations, where the air showers pass through a larger atmospheric depth. The distribution of the offsets between the directions of both experiments is found to decrease linearly with increasing signal-to-noise ratio. Significantly increased offsets and enhanced signal strengths are found in events which were modified by strong electric fields in thunderstorm clouds. Conclusions. We conclude that the angular resolution of LOPES is sufficient to determine the direction which maximizes the observed electric field amplitude. However, the statistical uncertainty of the directions is not determined by the resolution of LOPES, but by the uncertainty of the curvature radius. We do not find any systematic deviation between the directions determined from the radio signal and from the detected particles. This result places a strong supportive argument for the use of the radio technique to study the origin of high-energy cosmic rays.

KW - Acceleration of particles

KW - Elementary particles

KW - Instrumentation: detectors

KW - Methods: observational

KW - Radiation mechanisms: non-thermal

KW - Techniques: image processing

UR - http://www.scopus.com/inward/record.url?scp=48849113859&partnerID=8YFLogxK

U2 - 10.1051/0004-6361:20079218

DO - 10.1051/0004-6361:20079218

M3 - Article

SN - 0004-6361

VL - 487

SP - 781

EP - 788

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

IS - 2

ER -

Direction identification in radio images of cosmic-ray air showers detected with LOPES and KASCADE

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