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355 results on '"BÄhren, L."'

1. Wide-band Simultaneous Observations of Pulsars: Disentangling Dispersion Measure and Profile Variations

Author

Hassall, T. E., Stappers, B. W., Hessels, J. W. T., Kramer, M., Alexov, A., Anderson, K., Coenen, T., Karastergiou, A., Keane, E. F., Kondratiev, V. I., Lazaridis, K., van Leeuwen, J., Noutsos, A., Serylak, M., Sobey, C., Verbiest, J. P. W., Weltevrede, P., Zagkouris, K., Fender, R., Wijers, R. A. M. J., Bahren, L., Bell, M. E., Broderick, J. W., Corbel, S., Daw, E. J., Dhillon, V. S., Eisloffel, J., Falcke, H., Griessmeier, J. -M., Jonker, P., Law, C., Markoff, S., Miller-Jones, J. C. A., Osten, R., Rol, E., Scaife, A. M. M., Scheers, B., Schellart, P., Spreeuw, H., Swinbank, J., ter Veen, S., Wise, M. W., Wijnands, R., Wucknitz, O., Zarka, P., Asgekar, A., Bell, M. R., Bentum, M. J., Bernardi, G., Best, P., Bonafede, A., Boonstra, A. J., Brentjens, M., Brouw, W. N., Bruggen, M., Butcher, H. R., Ciardi, B., Garrett, M. A., Gerbers, M., Gunst, A. W., van Haarlem, M. P., Heald, G., Hoeft, M., Holties, H., de Jong, A., Koopmans, L. V. E., Kuniyoshi, M., Kuper, G., Loose, G. M., Maat, P., Masters, J., McKean, J. P., Meulman, H., Mevius, M., Munk, H., Noordam, J. E., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pizzo, R., Polatidis, A., Reich, W., Rottgering, H., Sluman, J., Steinmetz, M., Sterks, C. G. M., Tagger, M., Tang, Y., Tasse, C., Vermeulen, R., van Weeren, R. J., Wijnholds, S. J., and Yatawatta, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Dispersion in the interstellar medium is a well known phenomenon that follows a simple relationship, which has been used to predict the time delay of dispersed radio pulses since the late 1960s. We performed wide-band simultaneous observations of four pulsars with LOFAR (at 40-190 MHz), the 76-m Lovell Telescope (at 1400 MHz) and the Effelsberg 100-m Telescope (at 8000 MHz) to test the accuracy of the dispersion law over a broad frequency range. In this paper we present the results of these observations which show that the dispersion law is accurate to better than 1 part in 100000 across our observing band. We use this fact to constrain some of the properties of the ISM along the line-of-sight and use the lack of any aberration or retardation effects to determine upper limits on emission heights in the pulsar magnetosphere. We also discuss the effect of pulse profile evolution on our observations, and the implications that it could have for precision pulsar timing projects such as the detection of gravitational waves with pulsar timing arrays., Comment: 20 Pages, 14 Figures, Accepted for publication in Astronomy & Astrophysics

Published
2012
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2. LOFAR - Opening up a new window on the Universe

Author

Rottgering, H. J. A., Braun, R., Barthel, P. D., van Haarlem, M. P., Miley, G. K., Morganti, R., Snellen, I., Falcke, H., de Bruyn, A. G., Stappers, R. B., Boland, W. H. W. M., Butcher, H. R., de Geus, E. J., Koopmans, L., Fender, R., Kuijpers, J., Schilizzi, R. T., Vogt, C., Wijers, R. A. M. J., Wise, M., Brouw, W. N., Hamaker, J. P., Noordam, J. E., Oosterloo, T., Bahren, L., Brentjens, M. A., Wijnholds, S. J., Bregman, J. D., van Cappellen, W. A., Gunst, A. W., Kant, G. W., Reitsma, J., van der Schaaf, K., and de Vos, C. M.

Subjects
Astrophysics
Abstract

LOFAR, the Low Frequency Array, is a next-generation radio telescope that is being built in Northern Europe and expected to be fully operational at the end of this decade. It will operate at frequencies from 15 to 240 MHz (corresponding to wavelengths of 20 to 1.2 m). Its superb sensitivity, high angular resolution, large field of view and flexible spectroscopic capabilities will represent a dramatic improvement over previous facilities at these wavelengths. As such, LOFAR will carry out a broad range of fundamental astrophysical studies. The design of LOFAR has been driven by four fundamental astrophysical applications: (i) The Epoch of Reionisation, (ii) Extragalactic Surveys and their exploitation to study the formation and evolution of clusters, galaxies and black holes, (iii) Transient Sources and their association with high energy objects such as gamma ray bursts, and (iv) Cosmic Ray showers and their exploitation to study the origin of ultra-high energy cosmic rays. In this conference the foreseen LOFAR work on the epoch of reionisation has been covered by de Bruyn and on cosmic ray showers by Falcke. During this contribution we will first present the LOFAR project with an emphasis on the challenges faced when carrying out sensitive imaging at low radio frequencies. Subsequently, we will discuss LOFAR's capabilities to survey the low-frequency radio sky. Main aims for the planned surveys are studies of z>6 radio galaxies, diffuse emission associated with distant clusters and starbursting galaxies at z>2., Comment: 11 pages, 5 figures, to appear in the proceedings of the conference "Cosmology, galaxy formation and astroparticle physics on the pathway to the SKA", Oxford, April 10-12 2006

Published
2006

3. LOPES 3D -- studies on the benefits of EAS-radio measurements with vertically aligned antennas

Author

Huber, D., Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Huber, D., Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

The LOPES experiment was a radio interferometer built at the existing air shower array KASCADE-Grande in Karlsruhe, Germany. The last configuration of LOPES was called LOPES 3D and consisted of ten tripole antennas. Each of these antennas consisted of three crossed dipoles east-west, north-south, and vertically aligned. With this, LOPES 3D had the unique possibility to study the benefits of measurements with vertically aligned antennas in the environment of the well understood and calibrated particle detector array KASCADE-Grande. The measurements with three spatially coincident antennas allows a redundant reconstruction of the electric field vector. Several methods to exploit the redundancy were developed and tested. Furthermore, for the first time in LOPES, the background noise could be studied polarization- and direction dependent. With LOPES 3D it could be demonstrated that radio detection reaches a higher efficiency for inclined showers when including measurements with vertically aligned antennas and that the vertical component gets more important for the measurement of inclined showers. In this contribution we discuss a weighting scheme for the best combination of three redundant reconstructed electric field vectors. Furthermore, we discuss the influence of these weighting schemes on the ability to reconstruct air showers using the radio method. We show an estimate of the radio efficiency for inclined showers with focus on the benefits of measurements with vertically aligned antennas and we present the direction dependent noise in the different polarizations., Comment: Submission to the proceedings of the ARENA2014 workshop, which unfortunately were never published; thus documented here for reference

Published
2022

4. Final results of the LOPES radio interferometer for cosmic-ray air showers

Author

Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Falcke, H., Hörandel, J.R., Kuijpers, J.M.E., Zabierowski, J., Zensus, J.A., Collaboration, L., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Falcke, H., Hörandel, J.R., Kuijpers, J.M.E., Zabierowski, J., Zensus, J.A., and Collaboration, L.

Abstract

Contains fulltext : 230774.pdf (publisher's version ) (Open Access)

Published
2021

5. Final results of the LOPES radio interferometer for cosmic-ray air showers

Author

Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Collaboration, LOPES, Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., and Collaboration, LOPES

Abstract

LOPES, the LOFAR prototype station, was an antenna array for cosmic-ray air showers operating from 2003 - 2013 within the KASCADE-Grande experiment. Meanwhile, the analysis is finished and the data of air-shower events measured by LOPES are available with open access in the KASCADE Cosmic Ray Data Center (KCDC). This article intends to provide a summary of the achievements, results, and lessons learned from LOPES. By digital, interferometric beamforming the detection of air showers became possible in the radio-loud environment of the Karlsruhe Institute of Technology (KIT). As a prototype experiment, LOPES tested several antenna types, array configurations and calibration techniques, and pioneered analysis methods for the reconstruction of the most important shower parameters, i.e., the arrival direction, the energy, and mass-dependent observables such as the position of the shower maximum. In addition to a review and update of previously published results, we also present new results based on end-to-end simulations including all known instrumental properties. For this, we applied the detector response to radio signals simulated with the CoREAS extension of CORSIKA, and analyzed them in the same way as measured data. Thus, we were able to study the detector performance more accurately than before, including some previously inaccessible features such as the impact of noise on the interferometric cross-correlation beam. These results led to several improvements, which are documented in this paper and can provide useful input for the design of future cosmic-ray experiments based on the digital radio-detection technique., Comment: Accepted for publication by EPJ C

Published
2021
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6. Detection and imaging of atmospheric radio flashes from cosmic ray air showers

Author

Falcke, H., Apel, W. D., Badea, A. F., Bähren, L., Bekk, K., Bercuci, A., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buitink, S., Brüggemann, M., Buchholz, P., Butcher, H., Chiavassa, A., Daumiller, K., de Bruyn, A. G., de Vos, C. M., Di Pierro, F., Doll, P., Engel, R., Gemmeke, H., Ghia, P. L., Glasstetter, R., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Kampert, K.-H., Kant, G. W., Klein, U., Kolotaev, Y., Koopman, Y., Krömer, O., Kuijpers, J., Lafebre, S., Maier, G., Mathes, H. J., Mayer, H. J., Milke, J., Mitrica, B., Morello, C., Navarra, G., Nehls, S., Nigl, A., Obenland, R., Oehlschläger, J., Ostapchenko, S., Over, S., Pepping, H. J., Petcu, M., Petrovic, J., Plewnia, S., Rebel, H., Risse, A., Roth, M., Schieler, H., Schoonderbeek, G., Sima, O., Stümpert, M., Toma, G., Trinchero, G. C., Ulrich, H., Valchierotti, S., van Buren, J., van Cappellen, W., Walkowiak, W., Weindl, A., Wijnholds, S., Wochele, J., Zabierowski, J., Zensus, J. A., and Zimmermann, D.

Published
2005

7. Recent results of the LOPES experiment

Author

Bähren, L., Buitink, S.J., Falcke, H.D.E., Hörandel, J.R., Horneffer, K.H.A., and Kuijpers, J.M.E.

Subjects
Astronomy
Abstract

Contains fulltext : 75984.pdf (Publisher’s version ) (Closed access) 4 p.

Published
2009

8. Investigation of the radio wavefront of air showers with LOPES measurements and CoREAS simulations (ARENA 2014)

Author

Schröder, F. G., Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H, Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Sima, O., Toma, G., Gian Carlo Trinchero, Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

We investigated the radio wavefront of cosmic-ray air showers with LOPES measurements and CoREAS simulations: the wavefront is of approximately hyperbolic shape and its steepness is sensitive to the shower maximum. For this study we used 316 events with an energy above 0.1 EeV and zenith angles below $45^\circ$ measured by the LOPES experiment. LOPES was a digital radio interferometer consisting of up to 30 antennas on an area of approximately 200 m x 200 m at an altitude of 110 m above sea level. Triggered by KASCADE-Grande, LOPES measured the radio emission between 43 and 74 MHz, and our analysis might strictly hold only for such conditions. Moreover, we used CoREAS simulations made for each event, which show much clearer results than the measurements suffering from high background. A detailed description of our result is available in our recent paper published in JCAP09(2014)025. The present proceeding contains a summary and focuses on some additional aspects, e.g., the asymmetry of the wavefront: According to the CoREAS simulations the wavefront is slightly asymmetric, but on a much weaker level than the lateral distribution of the radio amplitude., Comment: Proceedings of ARENA 2014, Anapolis, USA

Published
2015
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9. A comparison of the cosmic-ray energy scales of Tunka-133 and KASCADE-Grande via their radio extensions Tunka-Rex and LOPES

Author

Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bezyazeekov, P.A., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Budnev, N.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fedorov, O., Fuchs, B., Gemmeke, H., Gress, O.A., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Kazarina, Y., Kleifges, M., Korosteleva, E.E., Kostunin, D., Krömer, O., Kuijpers, J.M.E., Kuzmichev, L.A., Link, K., Lubsandorzhiev, N., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Mirgazov, R.R., Monkhoev, R., Morello, C., Oehlschläger, J., Osipova, E.A., Pakhorukov, A., Palmieri, N., Pankov, L., Pierog, T., Prosin, V.V., Rautenberg, J., Rebel, H., Roth, M., Rubtsov, G.I., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wischnewski, R., Wochele, J., Zabierowski, J., Zagorodnikov, A., Zensus, J.A., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bezyazeekov, P.A., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Budnev, N.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fedorov, O., Fuchs, B., Gemmeke, H., Gress, O.A., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Kazarina, Y., Kleifges, M., Korosteleva, E.E., Kostunin, D., Krömer, O., Kuijpers, J.M.E., Kuzmichev, L.A., Link, K., Lubsandorzhiev, N., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Mirgazov, R.R., Monkhoev, R., Morello, C., Oehlschläger, J., Osipova, E.A., Pakhorukov, A., Palmieri, N., Pankov, L., Pierog, T., Prosin, V.V., Rautenberg, J., Rebel, H., Roth, M., Rubtsov, G.I., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wischnewski, R., Wochele, J., Zabierowski, J., Zagorodnikov, A., and Zensus, J.A.

Abstract

Contains fulltext : 165990.pdf (publisher's version ) (Open Access)

Published
2016

10. Improved absolute calibration of LOPES measurements and its impact on the comparison with REAS 3.11 and CoREAS simulations

Author

Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Krömer, O., Kuijpers, Jan, Link, K., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J.A., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Krömer, O., Kuijpers, Jan, Link, K., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J.A.

Abstract

Contains fulltext : 155766.pdf (preprint version ) (Open Access)

Published
2016

11. A comparison of the cosmic-ray energy scales of Tunka-133 and KASCADE-Grande via their radio extensions Tunka-Rex and LOPES

Author

Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bezyazeekov, P. A., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Budnev, N. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fedorov, O., Fuchs, B., Gemmeke, H., Gress, O. A., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Kazarina, Y., Kleifges, M., Korosteleva, E. E., Kostunin, D., Krömer, O., Kuijpers, J., Kuzmichev, L. A., Link, K., Lubsandorzhiev, N., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Mirgazov, R. R., Monkhoev, R., Morello, C., Oehlschläger, J., Osipova, E. A., Pakhorukov, A., Palmieri, N., Pankov, L., Pierog, T., Prosin, V. V., Rautenberg, J., Rebel, H., Roth, M., Rubtsov, G. I., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weind, A., Wischnewski, R., Wochele, J., Zabierowski, J., Zagorodnikov, A., Zensus, J. A., Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bezyazeekov, P. A., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Budnev, N. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fedorov, O., Fuchs, B., Gemmeke, H., Gress, O. A., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Kazarina, Y., Kleifges, M., Korosteleva, E. E., Kostunin, D., Krömer, O., Kuijpers, J., Kuzmichev, L. A., Link, K., Lubsandorzhiev, N., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Mirgazov, R. R., Monkhoev, R., Morello, C., Oehlschläger, J., Osipova, E. A., Pakhorukov, A., Palmieri, N., Pankov, L., Pierog, T., Prosin, V. V., Rautenberg, J., Rebel, H., Roth, M., Rubtsov, G. I., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weind, A., Wischnewski, R., Wochele, J., Zabierowski, J., Zagorodnikov, A., and Zensus, J. A.

Abstract

The radio technique is a promising method for detection of cosmic-ray air showers of energies around $100\,$PeV and higher with an array of radio antennas. Since the amplitude of the radio signal can be measured absolutely and increases with the shower energy, radio measurements can be used to determine the air-shower energy on an absolute scale. We show that calibrated measurements of radio detectors operated in coincidence with host experiments measuring air showers based on other techniques can be used for comparing the energy scales of these host experiments. Using two approaches, first via direct amplitude measurements, and second via comparison of measurements with air shower simulations, we compare the energy scales of the air-shower experiments Tunka-133 and KASCADE-Grande, using their radio extensions, Tunka-Rex and LOPES, respectively. Due to the consistent amplitude calibration for Tunka-Rex and LOPES achieved by using the same reference source, this comparison reaches an accuracy of approximately $10\,\%$ - limited by some shortcomings of LOPES, which was a prototype experiment for the digital radio technique for air showers. In particular we show that the energy scales of cosmic-ray measurements by the independently calibrated experiments KASCADE-Grande and Tunka-133 are consistent with each other on this level.

Published
2016
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12. A comparison of the cosmic-ray energy scales of Tunka-133 and KASCADE-Grande via their radio extensions Tunka-Rex and LOPES

Author

Apel, W.D., primary, Arteaga-Velázquez, J.C., additional, Bähren, L., additional, Bezyazeekov, P.A., additional, Bekk, K., additional, Bertaina, M., additional, Biermann, P.L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I.M., additional, Budnev, N.M., additional, Cantoni, E., additional, Chiavassa, A., additional, Daumiller, K., additional, de Souza, V., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Fedorov, O., additional, Fuchs, B., additional, Gemmeke, H., additional, Gress, O.A., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hiller, R., additional, Hörandel, J.R., additional, Horneffer, A., additional, Huber, D., additional, Huege, T., additional, Isar, P.G., additional, Kampert, K.-H., additional, Kang, D., additional, Kazarina, Y., additional, Kleifges, M., additional, Korosteleva, E.E., additional, Kostunin, D., additional, Krömer, O., additional, Kuijpers, J., additional, Kuzmichev, L.A., additional, Link, K., additional, Lubsandorzhiev, N., additional, Łuczak, P., additional, Ludwig, M., additional, Mathes, H.J., additional, Melissas, M., additional, Mirgazov, R.R., additional, Monkhoev, R., additional, Morello, C., additional, Oehlschläger, J., additional, Osipova, E.A., additional, Pakhorukov, A., additional, Palmieri, N., additional, Pankov, L., additional, Pierog, T., additional, Prosin, V.V., additional, Rautenberg, J., additional, Rebel, H., additional, Roth, M., additional, Rubtsov, G.I., additional, Rühle, C., additional, Saftoiu, A., additional, Schieler, H., additional, Schmidt, A., additional, Schoo, S., additional, Schröder, F.G., additional, Sima, O., additional, Toma, G., additional, Trinchero, G.C., additional, Weindl, A., additional, Wischnewski, R., additional, Wochele, J., additional, Zabierowski, J., additional, Zagorodnikov, A., additional, and Zensus, J.A., additional

Published
2016
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13. Improved absolute calibration of LOPES measurements and its impact on the comparison with REAS 3.11 and CoREAS simulations

Author

Apel, W.D., primary, Arteaga-Velázquez, J.C., additional, Bähren, L., additional, Bekk, K., additional, Bertaina, M., additional, Biermann, P.L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I.M., additional, Cantoni, E., additional, Chiavassa, A., additional, Daumiller, K., additional, de Souza, V., additional, Di Pierro, F., additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Fuchs, B., additional, Gemmeke, H., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hiller, R., additional, Hörandel, J.R., additional, Horneffer, A., additional, Huber, D., additional, Huege, T., additional, Isar, P.G., additional, Kampert, K.-H., additional, Kang, D., additional, Krömer, O., additional, Kuijpers, J., additional, Link, K., additional, Łuczak, P., additional, Ludwig, M., additional, Mathes, H.J., additional, Melissas, M., additional, Morello, C., additional, Nehls, S., additional, Oehlschläger, J., additional, Palmieri, N., additional, Pierog, T., additional, Rautenberg, J., additional, Rebel, H., additional, Roth, M., additional, Rühle, C., additional, Saftoiu, A., additional, Schieler, H., additional, Schmidt, A., additional, Schoo, S., additional, Schröder, F.G., additional, Sima, O., additional, Toma, G., additional, Trinchero, G.C., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, and Zensus, J.A., additional

Published
2016
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15. Revised absolute amplitude calibration of the LOPES experiment

Author

Link, K., Huege, T., Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Isar, P. G., Kampert, K-H., Kang, D., Krömer, O., Kuijpers, J., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Link, K., Huege, T., Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Isar, P. G., Kampert, K-H., Kang, D., Krömer, O., Kuijpers, J., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

One of the main aims of the LOPES experiment was the evaluation of the absolute amplitude of the radio signal of air showers. This is of special interest since the radio technique offers the possibility for an independent and highly precise determination of the energy scale of cosmic rays on the basis of signal predictions from Monte Carlo simulations. For the calibration of the amplitude measured by LOPES we used an external source. Previous comparisons of LOPES measurements and simulations of the radio signal amplitude predicted by CoREAS revealed a discrepancy of the order of a factor of two. A re-measurement of the reference calibration source, now performed for the free field, was recently performed by the manufacturer. The updated calibration values lead to a lowering of the reconstructed electric field measured by LOPES by a factor of $2.6 \pm 0.2$ and therefore to a significantly better agreement with CoREAS simulations. We discuss the updated calibration and its impact on the LOPES analysis results., Comment: Proceedings of the 34th ICRC, The Hague, The Netherlands, PoS(ICRC2015)311

Published
2015

16. Calibrating the absolute amplitude scale for air showers measured at LOFAR

Author

Nelles, A., Hörandel, J. R., Karskens, T., Krause, M., Buitink, S., Corstanje, A., Enriquez, J. E., Erdmann, M., Falcke, H., Haungs, A., Hiller, R., Huege, T., Krause, R., Link, K., Norden, M. J., Rachen, J. P., Rossetto, L., Schellart, P., Scholten, O., Schröder, F. G., ter Veen, S., Thoudam, S., Trinh, T. N. G., Weidenhaupt, K., Wijnholds, S. J., Anderson, J., Bähren, L., Bell, M. E., Bentum, M. J., Best, P., Bonafede, A., Bregman, J., Brouw, W. N., Bruüggen, M., Butcher, H. R., Carbone, D., Ciardi, B., de Gasperin, F., Duscha, S., Eislöffel, J., Fallows, R. A., Frieswijk, W., Garrett, M. A., van Haarlem, M. P., Heald, G., Hoeft, M., Horneffer, A., Iacobelli, M., Juette, E., Karastergiou, A., Kohler, J., Kondratiev, V. I., Kuniyoshi, M., Kuper, G., van Leeuwen, J., Maat, P., McFadden, R., McKay-Bukowski, D., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pizzo, R., Polatidis, A. G., Reich, W., Röttgering, H., Schwarz, D., Serylak, M., Sluman, J., Smirnov, O., Tasse, C., Toribio, M. C., Vermeulen, R., van Weeren, R. J., Wijers, R. A. M. J., Wucknitz, O., Zarka, P., Nelles, A., Hörandel, J. R., Karskens, T., Krause, M., Buitink, S., Corstanje, A., Enriquez, J. E., Erdmann, M., Falcke, H., Haungs, A., Hiller, R., Huege, T., Krause, R., Link, K., Norden, M. J., Rachen, J. P., Rossetto, L., Schellart, P., Scholten, O., Schröder, F. G., ter Veen, S., Thoudam, S., Trinh, T. N. G., Weidenhaupt, K., Wijnholds, S. J., Anderson, J., Bähren, L., Bell, M. E., Bentum, M. J., Best, P., Bonafede, A., Bregman, J., Brouw, W. N., Bruüggen, M., Butcher, H. R., Carbone, D., Ciardi, B., de Gasperin, F., Duscha, S., Eislöffel, J., Fallows, R. A., Frieswijk, W., Garrett, M. A., van Haarlem, M. P., Heald, G., Hoeft, M., Horneffer, A., Iacobelli, M., Juette, E., Karastergiou, A., Kohler, J., Kondratiev, V. I., Kuniyoshi, M., Kuper, G., van Leeuwen, J., Maat, P., McFadden, R., McKay-Bukowski, D., Orru, E., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pizzo, R., Polatidis, A. G., Reich, W., Röttgering, H., Schwarz, D., Serylak, M., Sluman, J., Smirnov, O., Tasse, C., Toribio, M. C., Vermeulen, R., van Weeren, R. J., Wijers, R. A. M. J., Wucknitz, O., and Zarka, P.

Abstract

Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These pulses have been measured successfully in the past few years at the LOw Frequency ARray (LOFAR) and are used to study the properties of cosmic rays. For a complete understanding of this phenomenon and the underlying physical processes, an absolute calibration of the detecting antenna system is needed. We present three approaches that were used to check and improve the antenna model of LOFAR and to provide an absolute calibration of the whole system for air shower measurements. Two methods are based on calibrated reference sources and one on a calibration approach using the diffuse radio emission of the Galaxy, optimized for short data-sets. An accuracy of 19% in amplitude is reached. The absolute calibration is also compared to predictions from air shower simulations. These results are used to set an absolute energy scale for air shower measurements and can be used as a basis for an absolute scale for the measurement of astronomical transients with LOFAR., Comment: 34 pages, 10 figures

Published
2015
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17. Improved absolute calibration of LOPES measurements and its impact on the comparison with REAS 3.11 and CoREAS simulations

Author

Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hiller, R., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Nehls, S., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

LOPES was a digital antenna array detecting the radio emission of cosmic-ray air showers. The calibration of the absolute amplitude scale of the measurements was done using an external, commercial reference source, which emits a frequency comb with defined amplitudes. Recently, we obtained improved reference values by the manufacturer of the reference source, which significantly changed the absolute calibration of LOPES. We reanalyzed previously published LOPES measurements, studying the impact of the changed calibration. The main effect is an overall decrease of the LOPES amplitude scale by a factor of $2.6 \pm 0.2$, affecting all previously published values for measurements of the electric-field strength. This results in a major change in the conclusion of the paper 'Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations' published in Astroparticle Physics 50-52 (2013) 76-91: With the revised calibration, LOPES measurements now are compatible with CoREAS simulations, but in tension with REAS 3.11 simulations. Since CoREAS is the latest version of the simulation code incorporating the current state of knowledge on the radio emission of air showers, this new result indicates that the absolute amplitude prediction of current simulations now is in agreement with experimental data., Comment: Partly changes results and conclusion of publication Astroparticle Physics 50-52 (2013) 76-91 (arXiv:1309.5920)

Published
2015
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18. Reconstructing energy and Xmax of cosmic ray air showers using the radio lateral distribution measured with LOPES

Author

Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, LOPES, FOS: Physical sciences, Cosmic ray, Digital radio, Computational physics, Interferometry, Distribution function, Air shower, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM), Noise (radio), Energy (signal processing)
Abstract

The LOPES experiment, a digital radio interferometer located at KIT (Karlsruhe Institute of Technology), obtained remarkable results for the detection of radio emission from extensive air showers at MHz frequencies. Features of the radio lateral distribution function (LDF) measured by LOPES are explored in this work for a precise reconstruction of two fundamental air shower parameters: the primary energy and the shower Xmax. The method presented here has been developed on (REAS3-)simulations, and is applied to LOPES measurements. Despite the high human-made noise at the LOPES site, it is possible to reconstruct both the energy and Xmax for individual events. On the one hand, the energy resolution is promising and comparable to the one of the co-located KASCADE-Grande experiment. On the other hand, Xmax values are reconstructed with the LOPES measurements with a resolution of 90 g/cm2 . A precision on Xmax better than 30 g/cm2 is predicted and achievable in a region with a lower human-made noise level., 9 pages, 5 figures, Proceedings ARENA 2012

Published
2013

19. Mass sensitivity in the radio lateral distribution function

Author

Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buchholz, P., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Finger, M., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Gian Carlo Trinchero, Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

Measuring the mass composition of ultra-high energy cosmic rays is one of the main tasks in the cosmic rays field. Here we are exploring the composition signature in the coherent electromagnetic emission from extensive air showers, detected in the MHz frequency range. One of the experiments that successfully detects radio events in the frequency band of 40-80 MHz is the LOPES experiment at KIT. It is a digital interferometric antenna array and has the important advantage of taking data in coincidence with the particle detector array KASCADE-Grande. A possible method to look at the composition signature in the radio data, predicted by simulations, concerns the radio lateral distribution function, since its slope is strongly correlated with Xmax. Recent comparison between REAS3 simulations and LOPES data showed a significantly improved agreement in the lateral distribution function and for this reason an analysis on a possible LOPES mass signature through the slope method is promising. Trying to reproduce a realistic case, proton and iron showers are simulated with REAS3 using the LOPES selection information as input parameters. The obtained radio lateral distribution slope is analyzed in detail. The lateral slope method to look at the composition signature in the radio data is shown here and a possible signature of mass composition in the LOPES data is discussed., Comment: 7 pages, 5 figures

Published
2013
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20. Comparison of LOPES data and CoREAS simulations using a full detector simulation (ICRC2013)

Author

Link, K., Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K-H, Kang, D., Krömer, O., Kuijpers, J., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Gian Carlo Trinchero, Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The LOPES experiment at the Karlsruhe Institute of Technology, Germany, has been measuring radio emission of air showers for almost 10 years. For a better understanding of the emission process a detailed comparison of data with simulations is necessary. This is possible using a newly developed detector simulation including all LOPES detector components. After propagating a simulated event through this full detector simulation a standard LOPES like event file is written. LOPES data and CoREAS simulations can then be treated equally and the same analysis software can be applied to both. This gives the opportunity to compare data and simulations directly. Furthermore, the standard analysis software can be used with simulations which provide the possibility to check the accuracy regarding reconstruction of air shower parameters. We point out the advantages and present first results using such a full LOPES detector simulation. A comparison of LOPES data and the Monte Carlo code CoREAS based on an analysis using this detector simulation is shown., Comment: 4 pages, presented at the International Cosmic Ray Conference, Rio de Janeiro, 2013, paper ID 0844

Published
2013
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21. Cosmic Ray Measurements with LOPES: Status and Recent Results (ARENA 2012)

Author

Schröder, F. G., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

LOPES is a digital antenna array at the Karlsruhe Institute of Technology, Germany, for cosmic-ray air-shower measurements. Triggered by the co-located KASCADE-Grande air-shower array, LOPES detects the radio emission of air showers via digital radio interferometry. We summarize the status of LOPES and recent results. In particular, we present an update on the reconstruction of the primary-particle properties based on almost 500 events above 100 PeV. With LOPES, the arrival direction can be reconstructed with a precision of at least 0.65{\deg}, and the energy with a precision of at least 20 %, which, however, does not include systematic uncertainties on the absolute energy scale. For many particle and astrophysics questions the reconstruction of the atmospheric depth of the shower maximum, Xmax, is important, since it yields information on the type of the primary particle and its interaction with the atmosphere. Recently, we found experimental evidence that the slope of the radio lateral distribution is indeed sensitive to the longitudinal development of the air shower, but unfortunately, the Xmax precision at LOPES is limited by the high level of anthropogenic radio background. Nevertheless, the developed methods can be transferred to next generation experiments with lower background, which should provide an Xmax precision competitive to other detection technologies., Comment: The following article has been accepted by AIP Conference Proceedings. Proceedings of ARENA 2012, Erlangen, Germany; to appear on http://proceedings.aip.org/

Published
2013
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22. LOPES 3D reconfiguration and first measurements

Author

Huber, D., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buchholz, P., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Finger, M., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Isar, P. G., Kampert, K. -H, Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Gian Carlo Trinchero, Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and Zensus, J. A.

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The Radio detection technique of high-energy cosmic rays is based on the radio signal emitted by the charged particles in an air shower due to their deflection in the Earth's magnetic field. The LOPES experiment at Karlsruhe Institute of Technology, Germany with its simple dipoles made major contributions to the revival of this technique. LOPES is working in the frequency range from 40 to 80 MHz and was reconfigured several times to improve and further develop the radio detection technique. In the current setup LOPES consists of 10 tripole antennas which measure the complete electric field vector of the radio emission from cosmic rays. LOPES is the first experiment measuring all three vectorial components at once and thereby gaining the full information about the electric field vector and not only a two-dimensional projection. Such a setup including also measurements of the vertical electric field component is expected to increase the sensitivity to inclined showers and help to advance the understanding of the emission mechanism. We present the reconfiguration and calibration procedure of LOPES 3D and discuss first measurements., Comment: Proceedings

Published
2013
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23. Status of LOFAR Data in HDF5 Format

Author

Alexov, A., Schellart, P., Veen, S. ter, Akker, M. van den, Bähren, L., Greissmeier, J.-M., Hessels, J.W.T., Mol, J.D., Renting, G.A., Swinbank, J., Wise, M., Egret, D., Lorente, N.P.F., Ballester, P., High Energy Astrophys. & Astropart. Phys (API, FNWI), Netherlands Institute for Radio Astronomy (ASTRON), Radboud university [Nijmegen], Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), P. Ballester & D. Egret & N.P.F. Lorente, and Ballester, P.

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU]Sciences of the Universe [physics], Astronomy, Astronomical Society of the Pacific Conference Series
Abstract

International audience; The Hierarchical Data Format, version 5 (HDF5) is a data model, library, and file format for storing and managing data. It is designed for flexible and efficient I/O and for high volume, complex data. The Low Frequency Array (LOFAR) project is solving the challenge of data size and complexity using HDF5. Most of LOFAR's standard data products will be stored using HDF5; the beam-formed time-series data and transient buffer board data have already transitioned from project-specific binary format to HDF5. We report on our effort to pave the way towards new astronomical data encapsulation using HDF5, which can be used by future ground and space projects. The LOFAR project has formed a collaboration with NRAO, the Virtual Astronomical Observatory (VAO) and the HDF Group to obtain funding for a full-time staff member to work on documenting and developing standards for astronomical data written in HDF5. We hope our effort will enhance HDF5 visibility and usage within the community, specifically for LSST, the SKA pathfinders (ASKAP, MeerKAT, MWA, LWA), and other major new radio telescopes such as EVLA, ALMA, and eMERLIN.

Published
2012

24. Towards HDF5: Encapsulation of Large and/or Complex Astronomical Data

Author

Wise, M., Alexov, A., Folk, M., Pierfederici, F., Anderson, K., Bähren, L., Evans, I.N., Accomazzi, A., Mink, D.J., Rots, A.H., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Abstract

The size and complexity of astronomical data are growing at relentless rates. This increase is especially apparent in the radio community as evidenced by the data challenges faced by many of the SKA pathfinders and other major new radio telescopes such as LOFAR, EVLA, ALMA, ASKAP, MeerKAT, MWA, LWA, and eMERLIN. Enormous data rates are also becoming a challenge for large optical projects that are currently ramping up including Pan-Starrs and LSST. As progress towards meeting these challenges, ASTRON and the LOFAR project are currently exploring the use of the Hierarchical Data Format, version 5 (HDF5) for LOFAR radio data encapsulation. In this session, we brought together scientists and developers struggling with large and complex datasets as well as those groups currently exploring HDF5 implementations. This paper briefly summarizes the BoF presentations, material discussed and future goals.

Published
2011

25. LOFAR and HDF5: toward a new radio data standard

Author

Anderson, K., Alexov, A., Bähren, L., Grießmeier, J.-M., Wise, M., Renting, G.A., Evans, I.N., Accomazzi, A., Mink, D.J., Rots, A.H., and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Abstract

For decades now, scientific data volumes have experienced relentless, exponential growth. As a result, legacy astronomical data formats are straining under a burden not conceived of when these formats were first introduced. With future astronomical projects ensuring this trend, ASTRON and the LOFAR project are exploring the use of the Hierarchical Data Format version 5 (HDF5) for LOFAR radio data encapsulation. Most of LOFAR's standard data products will be stored natively using the HDF5 format. In addition, HDF5 analogues for traditional radio data structures such as visibility data and spectral image cubes are also being developed. The HDF5 libraries allow for the construction of potentially distributed, entirely unbound files. The nature of the HDF5 format further provides the ability to custom design a data encapsulation format. The LOFAR project has designed several data formats that will accommodate all LOFAR data products, examples of which are presented in this paper. With proper development and support, it is hoped that these data formats will be adopted by other astronomical projects as they, too, attempt to grapple with a future filled with mountains of data.

Published
2011

26. LOFAR: Detecting Cosmic Rays with a Radio Telescope

Author

Corstanje, A., Akker, M. van den, Bähren, L., Falcke, H., Frieswijk, W., Hörandel, J. R., Horneffer, A., James, C. W., Kelley, J. L., McFadden, R., Mevius, M., Nelles, A., Schellart, P., Scholten, O., Thoudam, S., ter Veen, S., Research unit Astroparticle Physics, and Astronomy

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

LOFAR (the Low Frequency Array), a distributed digital radio telescope with stations in the Netherlands, Germany, France, Sweden, and the United Kingdom, is designed to enable full-sky monitoring of transient radio sources. These capabilities are ideal for the detection of broadband radio pulses generated in cosmic ray air showers. The core of LOFAR consists of 24 stations within 4 square kilometers, and each station contains 96 low-band antennas and 48 high-band antennas. This dense instrumentation will allow detailed studies of the lateral distribution of the radio signal in a frequency range of 10-250 MHz. Such studies are key to understanding the various radio emission mechanisms within the air shower, as well as for determining the potential of the radio technique for primary particle identification. We present the status of the LOFAR cosmic ray program, including the station design and hardware, the triggering and filtering schemes, and our initial observations of cosmic-ray-induced radio pulses., Comment: Contribution to the 32nd International Cosmic Ray Conference (Beijing, China, 11-18 Aug. 2011); 4 pages, 4 figures

Published
2011

27. Calibrating the absolute amplitude scale for air showers measured at LOFAR

Author

Nelles, A., primary, Hörandel, J. R., additional, Karskens, T., additional, Krause, M., additional, Buitink, S., additional, Corstanje, A., additional, Enriquez, J. E., additional, Erdmann, M., additional, Falcke, H., additional, Haungs, A., additional, Hiller, R., additional, Huege, T., additional, Krause, R., additional, Link, K., additional, Norden, M. J., additional, Rachen, J. P., additional, Rossetto, L., additional, Schellart, P., additional, Scholten, O., additional, Schröder, F. G., additional, Veen, S. ter, additional, Thoudam, S., additional, Trinh, T. N. G., additional, Weidenhaupt, K., additional, Wijnholds, S. J., additional, Anderson, J., additional, Bähren, L., additional, Bell, M. E., additional, Bentum, M. J., additional, Best, P., additional, Bonafede, A., additional, Bregman, J., additional, Brouw, W. N., additional, Brüggen, M., additional, Butcher, H. R., additional, Carbone, D., additional, Ciardi, B., additional, de Gasperin, F., additional, Duscha, S., additional, Eislöffel, J., additional, Fallows, R. A., additional, Frieswijk, W., additional, Garrett, M. A., additional, Haarlem, M. P. van, additional, Heald, G., additional, Hoeft, M., additional, Horneffer, A., additional, Iacobelli, M., additional, Juette, E., additional, Karastergiou, A., additional, Kohler, J., additional, Kondratiev, V. I., additional, Kuniyoshi, M., additional, Kuper, G., additional, Leeuwen, J. van, additional, Maat, P., additional, McFadden, R., additional, McKay-Bukowski, D., additional, Orru, E., additional, Paas, H., additional, Pandey-Pommier, M., additional, Pandey, V. N., additional, Pizzo, R., additional, Polatidis, A. G., additional, Reich, W., additional, Röttgering, H., additional, Schwarz, D., additional, Serylak, M., additional, Sluman, J., additional, Smirnov, O., additional, Tasse, C., additional, Toribio, M. C., additional, Vermeulen, R., additional, Weeren, R. J. van, additional, Wijers, R. A. M. J., additional, Wucknitz, O., additional, and Zarka, P., additional

Published
2015
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28. LOPES — Recent Results and Open Questions on the Radio Detection of Air Showers

Author

Schröder, F G, primary, Apel, W D, additional, Arteaga-Velázquez, J C, additional, Bähren, L, additional, Bekk, K, additional, Bertaina, M, additional, Biermann, P L, additional, Blümer, J, additional, Bozdog, H, additional, Brancus, I M, additional, Cantoni, E, additional, Chiavassa, A, additional, Daumiller, K, additional, de Souza, V, additional, Pierro, F Di, additional, Doll, P, additional, Engel, R, additional, Falcke, H, additional, Fuchs, B, additional, Gemmeke, H, additional, Grupen, C, additional, Haungs, A, additional, Heck, D, additional, Hörandel, J R, additional, Horneffer, A, additional, Huber, D, additional, Huege, T, additional, Isar, P G, additional, Kampert, K-H, additional, Kang, D, additional, Krömer, O, additional, Kuijpers, J, additional, Link, K, additional, Łuczak, P, additional, Ludwig, M, additional, Mathes, H J, additional, Melissas, M, additional, Morello, C, additional, Oehlschläger, J, additional, Palmieri, N, additional, Pierog, T, additional, Rautenberg, J, additional, Rebel, H, additional, Roth, M, additional, Rühle, C, additional, Saftoiu, A, additional, Schieler, H, additional, Schmidt, A, additional, Schoo, S, additional, Sima, O, additional, Toma, G, additional, Trinchero, G C, additional, Weindl, A, additional, Wochele, J, additional, Zabierowski, J, additional, and Zensus, J A, additional

Published
2015
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29. Pulsar polarisation below 200 MHz: Average profiles and propagation effects

Author

Noutsos, A., primary, Sobey, C., additional, Kondratiev, V. I., additional, Weltevrede, P., additional, Verbiest, J. P. W., additional, Karastergiou, A., additional, Kramer, M., additional, Kuniyoshi, M., additional, Alexov, A., additional, Breton, R. P., additional, Bilous, A. V., additional, Cooper, S., additional, Falcke, H., additional, Grießmeier, J.-M., additional, Hassall, T. E., additional, Hessels, J. W. T., additional, Keane, E. F., additional, Osłowski, S., additional, Pilia, M., additional, Serylak, M., additional, Stappers, B. W., additional, ter Veen, S., additional, van Leeuwen, J., additional, Zagkouris, K., additional, Anderson, K., additional, Bähren, L., additional, Bell, M., additional, Broderick, J., additional, Carbone, D., additional, Cendes, Y., additional, Coenen, T., additional, Corbel, S., additional, Eislöffel, J., additional, Fender, R., additional, Garsden, H., additional, Jonker, P., additional, Law, C., additional, Markoff, S., additional, Masters, J., additional, Miller-Jones, J., additional, Molenaar, G., additional, Osten, R., additional, Pietka, M., additional, Rol, E., additional, Rowlinson, A., additional, Scheers, B., additional, Spreeuw, H., additional, Staley, T., additional, Stewart, A., additional, Swinbank, J., additional, Wijers, R., additional, Wijnands, R., additional, Wise, M., additional, Zarka, P., additional, and van der Horst, A., additional

Published
2015
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30. Reconstruction of the energy and depth of maximum of cosmic-ray air-showers from LOPES radio measurements

Author

Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga-Velazquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

LOPES is a digital radio interferometer located at Karlsruhe Institute of Technology (KIT), Germany, which measures radio emission from extensive air showers at MHz frequencies in coincidence with KASCADE-Grande. In this article, we explore a method (slope method) which leverages the slope of the measured radio lateral distribution to reconstruct crucial attributes of primary cosmic rays. First, we present an investigation of the method on the basis of pure simulations. Second, we directly apply the slope method to LOPES measurements. Applying the slope method to simulations, we obtain uncertainties on the reconstruction of energy and depth of shower maximum Xmax of 13% and 50 g/cm^2, respectively. Applying it to LOPES measurements, we are able to reconstruct energy and Xmax of individual events with upper limits on the precision of 20-25% for the primary energy and 95 g/cm^2 for Xmax, despite strong human-made noise at the LOPES site., Comment: 16 pages, accepted by Physical Review D

Published
2014
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31. The wavefront of the radio signal emitted by cosmic ray air showers

Author

Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga-Velázquez, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schoo, S., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

Analyzing measurements of the LOPES antenna array together with corresponding CoREAS simulations for more than 300 measured events with energy above $10^{17}\,$eV and zenith angles smaller than $45^\circ$, we find that the radio wavefront of cosmic-ray air showers is of approximately hyperbolic shape. The simulations predict a slightly steeper wavefront towards East than towards West, but this asymmetry is negligible against the measurement uncertainties of LOPES. At axis distances $\gtrsim 50\,$m, the wavefront can be approximated by a simple cone. According to the simulations, the cone angle is clearly correlated with the shower maximum. Thus, we confirm earlier predictions that arrival time measurements can be used to study the longitudinal shower development, but now using a realistic wavefront. Moreover, we show that the hyperbolic wavefront is compatible with our measurement, and we present several experimental indications that the cone angle is indeed sensitive to the shower development. Consequently, the wavefront can be used to statistically study the primary composition of ultra-high energy cosmic rays. At LOPES, the experimentally achieved precision for the shower maximum is limited by measurement uncertainties to approximately $140\,$g/cm$^2$. But the simulations indicate that under better conditions this method might yield an accuracy for the atmospheric depth of the shower maximum, $X_\mathrm{max}$, better than $30\,$g/cm$^2$. This would be competitive with the established air-fluorescence and air-Cherenkov techniques, where the radio technique offers the advantage of a significantly higher duty-cycle. Finally, the hyperbolic wavefront can be used to reconstruct the shower geometry more accurately, which potentially allows a better reconstruction of all other shower parameters, too., Comment: accepted by JCAP

Published
2014
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32. Recent Results from KASCADE-Grande and LOPES

Author

Kampert, K.H., Bähren, L., Buitink, S.J., Falcke, H.D.E., Hörandel, J.R., Horneffer, K.H.A., Kuijpers, J.M.E., Lafèbre, S.J., Nigl, A., and Singh, K.

Subjects
Astronomy
Abstract

Contains fulltext : 75982.pdf (Publisher’s version ) (Closed access) 10 p.

Published
2009

33. Implementation of trigger for detection of ultra high energy cosmic rays with LOFAR

Author

Singh, K., Bähren, L., Falcke, H., Horneffer, A., Kooistra, E., Olaf Scholten, Research unit Nuclear & Hadron Physics, and Research unit Astroparticle Physics

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics
Abstract

Using all stations of LOFAR we are planning to explore the possibility of using Moon as a detector of ultra high energy (>10 21 eV) cosmic rays. The idea is to cover the whole visible lunar surface and to look for short pulses of Cherenkov radiation emitted by showers induced just below the surface of the Moon when the cosmic rays strike it. In the LOFAR station, a large number of digital data streams coming from the receivers are filtered and combined into a single, beamformed digital signal stream per station. This processing takes place in the cascade of a filterbank and a beam-former at station level, however triggering for radio pulses will be performed on a tied array beam formed at central processing level. Therefore, in order to implement this trigger we need to invert the station level digital processing at central processing level to achieve the required accuracy for triggering of real time signal. Additionally, pulse will be influenced by the ionosphere of the earth; therefore coherent dedispersion follow up is required to retrieve the original signal.

Published
2008

34. Air shower radio detection with LOPES

Author

Blumer, J., Apel, W.D., Arteaga, J.C., Asch, T., Auffenberg, J., Badea, F., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Bozdog, H., Brancus, I.M., Bruggemann, M., Buchholz, P., Buitink, S.J., Butcher, H., Chiavassa, A., Cossavella, F., Daumiller, K., Souza, V. de, Pierro, F. di, Doll, P., Engel, R., Falcke, H.D.E., Gemmeke, H., Ghia, P.L., Glasstetter, R., Grupen, C., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, K.H.A., Huege, T., Isar, P.G., Kampert, K.H., Kickelbick, D., Kolotaev, Y., Kromer, O., Kuijpers, J.M.E., Lafebre, S.J., Luczak, P., Mathes, H.J., Mayer, H.J., Meurer, C., Milke, J., Mitrica, B., Morello, C., Navarra, G., Nehls, S., Nigl, A., Oehlschlager, J., Ostapchenko, S., Over, S., Petcu, M., Petrovic, J., Pierog, T., Plewnia, S., Rautenberg, J., Rebel, H., Roth, M., Saftoiu, A., Schieler, H., Sima, O., Singh, K., Stumpert, M., Toma, G., Trinchero, G.C., Ulrich, H., Buren, J. van, Walkowiak, W., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J.A.

Subjects
Astronomy, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING
Abstract

Contains fulltext : 72639.pdf (Author’s version preprint ) (Open Access) 3 p.

Published
2008

35. Radio detection of cosmic ray air showers with LOPES

Author

Huege, T., Lopes, C., Apel, W.D., Asch, T., Badea, A.F., Bähren, L., Bekk, K., Bercuci, A., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Buitink, S.J., Brüggemann, M., Buchholz, P., Butcher, H., Chiavassa, A., Cossavella, F., Daumiller, K., Pierro, F. di, Doll, P., Engel, R., Falcke, H.D.E., Gemmeke, H., Ghia, P.L., Glasstetter, R., Grupen, C., Hakenjos, A., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, K.H.A., Isar, P.G., Kampert, K.H., Kolotaev, Y., Krömer, O., Kuijpers, J.M.E., Lafebre, S.J., Mathes, H.J., Mayer, H.J., Meurer, C., Milke, J., Mitrica, B., Morello, C., Navarra, G., Nehls, S., Nigl, A., Obenland, R., Oehlschläger, J., Ostapchenko, S., Over, S., Petcu, M., Petrovic, J., Pierog, T., Plewnia, S., Rebel, H., Risse, A., Roth, M., Schieler, H., Sima, O., Singh, K., Stümpert, M., Toma, G., Trinchero, G.C., Ulrich, H., Buren, J. van, Walkowiak, W., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J.A., and Zimmermann, D.

Subjects
Astronomy
Abstract

Contains fulltext : 36386.pdf (Author’s version preprint ) (Open Access) Electronic Article Available from Elsevier Science.

Published
2007

36. Radio detection of cosmic rays with LOPES (LOPES Collaboration)

Author

Grupen,C., Apel,W.D., Asch,T., Badea,A.F., Bähren,L., Bekk,K., Bercuci,A., Bertaina,M., Biermann,P.L., Blümer,J., Bozdog,H., Brancus,I.M., Buitink,S., Brüggemann,M., Buchholz,P., Butcher,H., Chiavassa,A., Cossavella,F., Daumiller,K., Di Pierro,F., Doll,P., Engel,R., Falcke,H., Gemmeke,H., Ghia,P.L., Glasstetter,R., Haungs,A., Heck,D., Hörandel,J.R., Horneffer,A., Huege,T., Kampert,K.H., Kolotaev,Y., Krömer,O., Kuijpers,J., Lafebre,S., Mathes,H.J., Mayer,H.J., Meurer,C., Milke,J., Mitrica,B., Morello,C., Navarra,G., Nehls,S., Nigl,A., Obenland,R., Oehlschläger,J., Ostapchenko,S., Over,S., Petcu,M., Petrovic,J., Pierog,T., Plewnia,S., Rebel,H., Roth,M., Schieler,H., Sima,O., Singh,K., Stümpert,M., Toma,G., Trinchero,G.C., Ulrich,H., van Buren,J., Walkowiak,W., Weindl,A., Wochele,J., Zabierowski,J., Zensus,J.A., and Zimmermann,D.

Subjects
Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Extensive air shower, Astrophysics::Instrumentation and Methods for Astrophysics, Radio emission, Cosmic rays
Abstract

Data taken with a radio antenna array in combination with the ground-level air shower experiment KASCADE-Grande at the Forschungszentrum Karlsruhe open up the possibility to measure large extensive air showers with this new technique. The pulse height of the observed radio signals scales with the primary energy of the particles initiating the air shower. The dependence of the radio signal on the angle of the shower axis with respect to the Earth's geomagnetic field and the coherence of the radiation suggest that the radio signal generation is due to the geosynchrotron mechanism.

Published
2006

37. Radio emission in air showers measured by LOPES-10 in coincidence with KASCADE-Grande observations

Author

Badea, A. F., Apel, W. D., Asch, T., Bähren, L., Bekk, K., Bercuci, A., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buitink, S., Brüggemann, M., Buchholz, P., Butcher, H., Chiavassa, A., Cossavella, F., Daumiller, K., Pierro, F. di, Doll, P., Engel, R., Falcke, H., Gemmeke, H., Ghia, P. L., Glasstetter, R., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Kampert, K. H., Kolotaev, Y., Krömer, O., Kuijpers, J., Lafebre, S., Mathes, H. J., Mayer, H. J., Meurer, C., Milke, J., Mitrica, B., Morello, C., Navarra, G., Nehls, S., Nigl, A., Obenland, R., Oehlschläger, J., Ostapchenko, S., Over, S., Petcu, M., Petrovic, J., Pierog, T., Plewnia, S., Rebel, H., Risse, A., Roth, M., Schieler, H., Sima, O., Singh, K., Stümpert, M., Toma, G., Trinchero, G. C., Ulrich, H., Buren, J. van, Walkowiak, W., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., and Zimmermann, D.

Subjects
Physics, ddc:530
Published
2006
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38. Radio emission of highly inclined cosmic ray air showers measured with LOPES - possibility for neutrino detection

Author

Petrovic, J., Bähren, L., Buitink, S.J., Falcke, H.D.E., Horneffer, K.H.A., Kuijpers, J.M.E., Lafebre, S.J., and Nigl, A.

Subjects
Physics::Instrumentation and Detectors, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, High Energy Physics::Experiment, Astrophysics::Cosmology and Extragalactic Astrophysics
Abstract

Contains fulltext : 35499.pdf ( ) (Open Access) LOPES - LOFAR PrototypE Station (LOFAR - LOw Frequency ARray) is an array of dipole antennas used for the detection of radio emission from cosmic ray air showers. It is co-located and triggered by the KASCADE (KArlsruhe Shower Core and Array Detector) experiment, which also provides information about air shower properties like electron number Ne, muon number N�, azimuth and zenith angle. LOPES-10 (the first phase of LOPES, consisting of 10 antennas) detected a significant number of cosmic ray air showers with a zenith angle larger than 50�, and many of those have very high field strengths. The most inclined event that has been detected with LOPES-10 has a zenith angle of almost 80�. This is important, because cosmic ray air showers with large inclinations, triggered close to the ground, would be a signature of neutrino events. Due to the small baseline of the LOPES-10 detector, it is not yet possible to determine accuratelly the radius of curvature of the showers front, which is related to the distance to the maximum of shower development. However, this should be possible in the future with a large baseline radio telescope like LOFAR.

Published
2006

39. The wavefront of the radio signal emitted by cosmic ray air showers

Author

Apel, W.D., primary, Arteaga-Velázquez, J.C., additional, Bähren, L., additional, Bekk, K., additional, Bertaina, M., additional, Biermann, P.L., additional, Blümer, J., additional, Bozdog, H., additional, Brancus, I.M., additional, Cantoni, E., additional, Chiavassa, A., additional, Daumiller, K., additional, de Souza, V., additional, Pierro, F. Di, additional, Doll, P., additional, Engel, R., additional, Falcke, H., additional, Fuchs, B., additional, Gemmeke, H., additional, Grupen, C., additional, Haungs, A., additional, Heck, D., additional, Hörandel, J.R., additional, Horneffer, A., additional, Huber, D., additional, Huege, T., additional, Isar, P.G., additional, Kampert, K.-H., additional, Kang, D., additional, Krömer, O., additional, Kuijpers, J., additional, Link, K., additional, Łuczak, P., additional, Ludwig, M., additional, Mathes, H.J., additional, Melissas, M., additional, Morello, C., additional, Oehlschläger, J., additional, Palmieri, N., additional, Pierog, T., additional, Rautenberg, J., additional, Rebel, H., additional, Roth, M., additional, Rühle, C., additional, Saftoiu, A., additional, Schieler, H., additional, Schmidt, A., additional, Schoo, S., additional, Schröder, F.G., additional, Sima, O., additional, Toma, G., additional, Trinchero, G.C., additional, Weindl, A., additional, Wochele, J., additional, Zabierowski, J., additional, and Zensus, J.A., additional

Published
2014
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40. Cosmic ray measurements with LOPES: Status and recent results

Author

Schroder, F.G., Apel, W.D., Arteaga-Velazquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Luczak, P., Rautenberg, J., Weindl, A., Zabierowski, J., Schroder, F.G., Apel, W.D., Arteaga-Velazquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Luczak, P., Rautenberg, J., Weindl, A., and Zabierowski, J.

Abstract

Contains fulltext : 117370.pdf (preprint version ) (Open Access)

Published
2013

41. Comparing lopes measurements of air-shower radio emission with reas 3.11 and coreas simulations

Author

Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F.D., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J.A., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Cantoni, E., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F.D., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H.J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J.A.

Abstract

Contains fulltext : 122863.pdf (preprint version ) (Open Access)

Published
2013

42. Comparison of lopes measurements with coreas and reas 3.11 simulations

Author

Ludwig, M., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haug, M., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.-H., Kang, D., Krömer, O., Kuijpers, J.M.E., Link, K., Łuczak, P., Mathes, H.J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J.A., Ludwig, M., Apel, W.D., Arteaga-Velázquez, J.C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P.L., Blümer, J., Bozdog, H., Brancus, I.M., Chiavassa, A., Daumiller, K., Souza, V. de, Pierro, F. Di, Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haug, M., Haungs, A., Heck, D., Hörandel, J.R., Horneffer, A., Huber, D., Huege, T., Isar, P.G., Kampert, K.-H., Kang, D., Krömer, O., Kuijpers, J.M.E., Link, K., Łuczak, P., Mathes, H.J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F.G., Sima, O., Toma, G., Trinchero, G.C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J.A.

Abstract

Contains fulltext : 122603.pdf (preprint version ) (Open Access)

Published
2013

43. Radio Measurements of Air Showers with LOPES

Author

Schröder, F.G., Bähren, L., Falcke, H., Hörandel, J.R., Zensus, J.A., Schröder, F.G., Bähren, L., Falcke, H., Hörandel, J.R., and Zensus, J.A.

Abstract

Contains fulltext : 117189.pdf (publisher's version ) (Open Access)

Published
2013

44. Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations

Author

Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

Cosmic ray air showers emit radio pulses at MHz frequencies, which can be measured with radio antenna arrays - like LOPES at the Karlsruhe Institute of Technology in Germany. To improve the understanding of the radio emission, we test theoretical descriptions with measured data. The observables used for these tests are the absolute amplitude of the radio signal, and the shape of the radio lateral distribution. We compare lateral distributions of more than 500 LOPES events with two recent and public Monte Carlo simulation codes, REAS 3.11 and CoREAS (v 1.0). The absolute radio amplitudes predicted by REAS 3.11 are in good agreement with the LOPES measurements. The amplitudes predicted by CoREAS are lower by a factor of two, and marginally compatible with the LOPES measurements within the systematic scale uncertainties. In contrast to any previous versions of REAS, REAS 3.11 and CoREAS now reproduce the shape of the measured lateral distributions correctly. This reflects a remarkable progress compared to the situation a few years ago, and it seems that the main processes for the radio emission of air showers are now understood: The emission is mainly due to the geomagnetic deflection of the electrons and positrons in the shower. Less important but not negligible is the Askaryan effect (net charge variation). Moreover, we confirm that the refractive index of the air plays an important role, since it changes the coherence conditions for the emission: Only the new simulations including the refractive index can reproduce rising lateral distributions which we observe in a few LOPES events. Finally, we show that the lateral distribution is sensitive to the energy and the mass of the primary cosmic ray particles., Comment: Attention: results and conclusion partly changed due to updated calibration. See Astroparticle Physics 75 (2016) 72-74; arXiv:1507.07389

Published
2013
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45. Detecting cosmic rays with the LOFAR radio telescope

Author

Schellart, P., Nelles, A., Buitink, S., Corstanje, A., Enriquez, J. E., Falcke, H., Frieswijk, W., Hörandel, J. R., Horneffer, A., James, C. W., Krause, M., Mevius, M., Scholten, O., ter Veen, S., Thoudam, S., Akker, M. van den, Alexov, A., Anderson, J., Avruch, I. M., Bähren, L., Beck, R., Bell, M. E., Bennema, P., Bentum, M. J., Bernardi, G., Best, P., Bregman, J., Breitling, F., Brentjens, M., Broderick, J., Brüggen, M., Ciardi, B., Coolen, A., de Gasperin, F., de Geus, E., de Jong, A., de Vos, M., Duscha, S., Eislöffel, J., Fallows, R. A., Ferrari, C., Garrett, M. A., Grießmeier, J., Grit, T., Hamaker, J. P., Hassall, T. E., Heald, G., Hessels, J. W. T., Hoeft, M., Holties, H. A., Iacobelli, M., Juette, E., Karastergiou, A., Klijn, W., Kohler, J., Kondratiev, V. I., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., McKean, J. P., Miller-Jones, J. C. A., Mol, J. D., Mulcahy, D. D., Munk, H., Nijboer, R., Norden, M. J., Orru, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A. G., Renting, A., Romein, J. W., Röttgering, H., Schoenmakers, A., Schwarz, D., Sluman, J., Smirnov, O., Sobey, C., Stappers, B. W., Steinmetz, M., Swinbank, J., Tang, Y., Tasse, C., Toribio, C., van Leeuwen, J., van Nieuwpoort, R., van Weeren, R. J., Vermaas, N., Vermeulen, R., Vocks, C., Vogt, C., Wijers, R. A. M. J., Wijnholds, S. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., Schellart, P., Nelles, A., Buitink, S., Corstanje, A., Enriquez, J. E., Falcke, H., Frieswijk, W., Hörandel, J. R., Horneffer, A., James, C. W., Krause, M., Mevius, M., Scholten, O., ter Veen, S., Thoudam, S., Akker, M. van den, Alexov, A., Anderson, J., Avruch, I. M., Bähren, L., Beck, R., Bell, M. E., Bennema, P., Bentum, M. J., Bernardi, G., Best, P., Bregman, J., Breitling, F., Brentjens, M., Broderick, J., Brüggen, M., Ciardi, B., Coolen, A., de Gasperin, F., de Geus, E., de Jong, A., de Vos, M., Duscha, S., Eislöffel, J., Fallows, R. A., Ferrari, C., Garrett, M. A., Grießmeier, J., Grit, T., Hamaker, J. P., Hassall, T. E., Heald, G., Hessels, J. W. T., Hoeft, M., Holties, H. A., Iacobelli, M., Juette, E., Karastergiou, A., Klijn, W., Kohler, J., Kondratiev, V. I., Kramer, M., Kuniyoshi, M., Kuper, G., Maat, P., Macario, G., Mann, G., Markoff, S., McKay-Bukowski, D., McKean, J. P., Miller-Jones, J. C. A., Mol, J. D., Mulcahy, D. D., Munk, H., Nijboer, R., Norden, M. J., Orru, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pizzo, R., Polatidis, A. G., Renting, A., Romein, J. W., Röttgering, H., Schoenmakers, A., Schwarz, D., Sluman, J., Smirnov, O., Sobey, C., Stappers, B. W., Steinmetz, M., Swinbank, J., Tang, Y., Tasse, C., Toribio, C., van Leeuwen, J., van Nieuwpoort, R., van Weeren, R. J., Vermaas, N., Vermeulen, R., Vocks, C., Vogt, C., Wijers, R. A. M. J., Wijnholds, S. J., Wise, M. W., Wucknitz, O., Yatawatta, S., Zarka, P., and Zensus, A.

Abstract

The low frequency array (LOFAR), is the first radio telescope designed with the capability to measure radio emission from cosmic-ray induced air showers in parallel with interferometric observations. In the first $\sim 2\,\mathrm{years}$ of observing, 405 cosmic-ray events in the energy range of $10^{16} - 10^{18}\,\mathrm{eV}$ have been detected in the band from $30 - 80\,\mathrm{MHz}$. Each of these air showers is registered with up to $\sim1000$ independent antennas resulting in measurements of the radio emission with unprecedented detail. This article describes the dataset, as well as the analysis pipeline, and serves as a reference for future papers based on these data. All steps necessary to achieve a full reconstruction of the electric field at every antenna position are explained, including removal of radio frequency interference, correcting for the antenna response and identification of the pulsed signal.

Published
2013
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46. Investigation on the energy and mass composition of cosmic rays using LOPES radio data

Author

Palmieri, N., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., J. A. Zensus - LOPES Collaboration, Palmieri, N., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and J. A. Zensus - LOPES Collaboration

Abstract

The sensitivity to the mass composition as well as the reconstruction of the energy of the primary particle are explored here by leveraging the features of the radio lateral distribution function. For the purpose of this analysis, a set of events measured with the LOPES experiment is reproduced with the latest CoREAS radio simulation code. Based on simulation predictions, a method which exploits the slope of the radio lateral distribution function is developed (Slope Method) and directly applied on measurements. As a result, the possibility to reconstruct both the energy and the depth of the shower maximum of the cosmic ray air shower using radio data and achieving relatively small uncertainties is presented., Comment: 10 pages, 6 figures, Proceedings for International Cosmic Ray Conference (ICRC) 2013, Rio De Janeiro; paper ID 439

Published
2013

47. Vectorial Radio Interferometry with LOPES 3D

Author

Huber, D., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., Zensus, J. A., Huber, D., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huege, T., Isar, P. G., Kampert, K. H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Łuczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmid, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and Zensus, J. A.

Abstract

One successful detection technique for high-energy cosmic rays is based on the radio signal emitted by the charged particles in an air shower. The LOPES experiment at Karlsruhe Institute of Technology, Germany, has made major contributions to the evolution of this technique. LOPES was reconfigured several times to improve and further develop the radio detection technique. In the latest setup LOPES consisted of 10 tripole antennas. With this, LOPES 3D was the first cosmic ray experiment measuring all three vectorial field components at once and thereby gaining the full information about the electric field vector. We present an analysis based on the data taken with special focus on the benefits of a direct measurement of the vertical polarization component. We demonstrate that by measuring all polarization components the detection and reconstruction efficiency is increased and noisy single channel data can be reconstructed by utilising the information from the other two channels of one antenna station., Comment: Proceedings of 33rd International Cosmic Ray Conference, RIO 2013

Published
2013

48. LOFAR: The LOw-Frequency ARray

Author

van Haarlem, M. P., Wise, M. W., Gunst, A. W., Heald, G., McKean, J. P., Hessels, J. W. T., de Bruyn, A. G., Nijboer, R., Swinbank, J., Fallows, R., Brentjens, M., Nelles, A., Beck, R., Falcke, H., Fender, R., Hörandel, J., Koopmans, L. V. E., Mann, G., Miley, G., Röttgering, H., Stappers, B. W., Wijers, R. A. M. J., Zaroubi, S., Akker, M. van den, Alexov, A., Anderson, J., Anderson, K., van Ardenne, A., Arts, M., Asgekar, A., Avruch, I. M., Batejat, F., Bähren, L., Bell, M. E., Bell, M. R., van Bemmel, I., Bennema, P., Bentum, M. J., Bernardi, G., Best, P., Bîrzan, L., Bonafede, A., Boonstra, A. -J., Braun, R., Bregman, J., Breitling, F., van de Brink, R. H., Broderick, J., Broekema, P. C., Brouw, W. N., Brüggen, M., Butcher, H. R., van Cappellen, W., Ciardi, B., Coenen, T., Conway, J., Coolen, A., Corstanje, A., Damstra, S., Davies, O., Deller, A. T., Dettmar, R. -J., van Diepen, G., Dijkstra, K., Donker, P., Doorduin, A., Dromer, J., Drost, M., van Duin, A., Eislöffel, J., van Enst, J., Ferrari, C., Frieswijk, W., Gankema, H., Garrett, M. A., de Gasperin, F., Gerbers, M., de Geus, E., Grießmeier, J. -M., Grit, T., Gruppen, P., Hamaker, J. P., Hassall, T., Hoeft, M., Holties, H., Horneffer, A., van der Horst, A., van Houwelingen, A., Huijgen, A., Iacobelli, M., Intema, H., Jackson, N., Jelic, V., de Jong, A., Juette, E., Kant, D., Karastergiou, A., Koers, A., Kollen, H., Kondratiev, V. I., Kooistra, E., Koopman, Y., Koster, A., Kuniyoshi, M., Kramer, M., Kuper, G., Lambropoulos, P., Law, C., van Leeuwen, J., Lemaitre, J., Loose, M., Maat, P., Macario, G., Markoff, S., Masters, J., McKay-Bukowski, D., Meijering, H., Meulman, H., Mevius, M., Middelberg, E., Millenaar, R., Miller-Jones, J. C. A., Mohan, R. N., Mol, J. D., Morawietz, J., Morganti, R., Mulcahy, D. D., Mulder, E., Munk, H., Nieuwenhuis, L., van Nieuwpoort, R., Noordam, J. E., Norden, M., Noutsos, A., Offringa, A. R., Olofsson, H., Omar, A., Orrú, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pizzo, R., Polatidis, A., Rafferty, D., Rawlings, S., Reich, W., de Reijer, J. -P., Reitsma, J., Renting, A., Riemers, P., Rol, E., Romein, J. W., Roosjen, J., Ruiter, M., Scaife, A., van der Schaaf, K., Scheers, B., Schellart, P., Schoenmakers, A., Schoonderbeek, G., Serylak, M., Shulevski, A., Sluman, J., Smirnov, O., Sobey, C., Spreeuw, H., Steinmetz, M., Sterks, C. G. M., Stiepel, H. -J., Stuurwold, K., Tagger, M., Tang, Y., Tasse, C., Thomas, I., Thoudam, S., Toribio, M. C., van der Tol, B., Usov, O., van Veelen, M., van der Veen, A. -J., ter Veen, S., Verbiest, J. P. W., Vermeulen, R., Vermaas, N., Vocks, C., Vogt, C., de Vos, M., van der Wal, E., van Weeren, R., Weggemans, H., Weltevrede, P., White, S., Wijnholds, S. J., Wilhelmsson, T., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., van Zwieten, J., van Haarlem, M. P., Wise, M. W., Gunst, A. W., Heald, G., McKean, J. P., Hessels, J. W. T., de Bruyn, A. G., Nijboer, R., Swinbank, J., Fallows, R., Brentjens, M., Nelles, A., Beck, R., Falcke, H., Fender, R., Hörandel, J., Koopmans, L. V. E., Mann, G., Miley, G., Röttgering, H., Stappers, B. W., Wijers, R. A. M. J., Zaroubi, S., Akker, M. van den, Alexov, A., Anderson, J., Anderson, K., van Ardenne, A., Arts, M., Asgekar, A., Avruch, I. M., Batejat, F., Bähren, L., Bell, M. E., Bell, M. R., van Bemmel, I., Bennema, P., Bentum, M. J., Bernardi, G., Best, P., Bîrzan, L., Bonafede, A., Boonstra, A. -J., Braun, R., Bregman, J., Breitling, F., van de Brink, R. H., Broderick, J., Broekema, P. C., Brouw, W. N., Brüggen, M., Butcher, H. R., van Cappellen, W., Ciardi, B., Coenen, T., Conway, J., Coolen, A., Corstanje, A., Damstra, S., Davies, O., Deller, A. T., Dettmar, R. -J., van Diepen, G., Dijkstra, K., Donker, P., Doorduin, A., Dromer, J., Drost, M., van Duin, A., Eislöffel, J., van Enst, J., Ferrari, C., Frieswijk, W., Gankema, H., Garrett, M. A., de Gasperin, F., Gerbers, M., de Geus, E., Grießmeier, J. -M., Grit, T., Gruppen, P., Hamaker, J. P., Hassall, T., Hoeft, M., Holties, H., Horneffer, A., van der Horst, A., van Houwelingen, A., Huijgen, A., Iacobelli, M., Intema, H., Jackson, N., Jelic, V., de Jong, A., Juette, E., Kant, D., Karastergiou, A., Koers, A., Kollen, H., Kondratiev, V. I., Kooistra, E., Koopman, Y., Koster, A., Kuniyoshi, M., Kramer, M., Kuper, G., Lambropoulos, P., Law, C., van Leeuwen, J., Lemaitre, J., Loose, M., Maat, P., Macario, G., Markoff, S., Masters, J., McKay-Bukowski, D., Meijering, H., Meulman, H., Mevius, M., Middelberg, E., Millenaar, R., Miller-Jones, J. C. A., Mohan, R. N., Mol, J. D., Morawietz, J., Morganti, R., Mulcahy, D. D., Mulder, E., Munk, H., Nieuwenhuis, L., van Nieuwpoort, R., Noordam, J. E., Norden, M., Noutsos, A., Offringa, A. R., Olofsson, H., Omar, A., Orrú, E., Overeem, R., Paas, H., Pandey-Pommier, M., Pandey, V. N., Pizzo, R., Polatidis, A., Rafferty, D., Rawlings, S., Reich, W., de Reijer, J. -P., Reitsma, J., Renting, A., Riemers, P., Rol, E., Romein, J. W., Roosjen, J., Ruiter, M., Scaife, A., van der Schaaf, K., Scheers, B., Schellart, P., Schoenmakers, A., Schoonderbeek, G., Serylak, M., Shulevski, A., Sluman, J., Smirnov, O., Sobey, C., Spreeuw, H., Steinmetz, M., Sterks, C. G. M., Stiepel, H. -J., Stuurwold, K., Tagger, M., Tang, Y., Tasse, C., Thomas, I., Thoudam, S., Toribio, M. C., van der Tol, B., Usov, O., van Veelen, M., van der Veen, A. -J., ter Veen, S., Verbiest, J. P. W., Vermeulen, R., Vermaas, N., Vocks, C., Vogt, C., de Vos, M., van der Wal, E., van Weeren, R., Weggemans, H., Weltevrede, P., White, S., Wijnholds, S. J., Wilhelmsson, T., Wucknitz, O., Yatawatta, S., Zarka, P., Zensus, A., and van Zwieten, J.

Abstract

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., Comment: 56 pages, 34 figures, accepted for publication by A&A

Published
2013
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49. LOPES 3D - vectorial measurements of radio emission from cosmic ray induced air showers

Author

Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Zabierowski, J., and Zensus, J. A.

Abstract

LOPES 3D is able to measure all three components of the electric field vector of the radio emission from air showers. This allows a better comparison with emission models. The measurement of the vertical component increases the sensitivity to inclined showers. By measuring all three components of the electric field vector LOPES 3D demonstrates by how much the reconstruction accuracy of primary cosmic ray parameters increases. Thus LOPES 3D evaluates the usefulness of vectorial measurements for large scale applications., Comment: Proceedings ARENA 2012

Published
2013

50. LOPES-3D, an antenna array for full signal detection of air-shower radio emission

Author

Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buchholz, P., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Finger, M., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., Zensus, J. A., Apel, W. D., Arteaga, J. C., Bähren, L., Bekk, K., Bertaina, M., Biermann, P. L., Blümer, J., Bozdog, H., Brancus, I. M., Buchholz, P., Cantoni, E., Chiavassa, A., Daumiller, K., de Souza, V., Di Pierro, F., Doll, P., Engel, R., Falcke, H., Finger, M., Fuchs, B., Fuhrmann, D., Gemmeke, H., Grupen, C., Haungs, A., Heck, D., Hörandel, J. R., Horneffer, A., Huber, D., Huege, T., Isar, P. G., Kampert, K. -H., Kang, D., Krömer, O., Kuijpers, J., Link, K., Luczak, P., Ludwig, M., Mathes, H. J., Melissas, M., Morello, C., Oehlschläger, J., Palmieri, N., Pierog, T., Rautenberg, J., Rebel, H., Roth, M., Rühle, C., Saftoiu, A., Schieler, H., Schmidt, A., Schröder, F. G., Sima, O., Toma, G., Trinchero, G. C., Weindl, A., Wochele, J., Wommer, M., Zabierowski, J., and Zensus, J. A.

Abstract

To better understand the radio signal emitted by extensive air-showers and to further develop the radio detection technique of high-energy cosmic rays, the LOPES experiment was reconfigured to LOPES-3D. LOPES-3D is able to measure all three vectorial components of the electric field of radio emission from cosmic ray air showers. The additional measurement of the vertical component ought to increase the reconstruction accuracy of primary cosmic ray parameters like direction and energy, provides an improved sensitivity to inclined showers, and will help to validate simulation of the emission mechanisms in the atmosphere. LOPES-3D will evaluate the feasibility of vectorial measurements for large scale applications. In order to measure all three electric field components directly, a tailor-made antenna type (tripoles) was deployed. The change of the antenna type necessitated new pre-amplifiers and an overall recalibration. The reconfiguration and the recalibration procedure are presented and the operationality of LOPES-3D is demonstrated.

Published
2013
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