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4 results on '"S. ter Veen"'

1. Updated Calibration of the LOFAR Low-Band Antennas

Author

Heino Falcke, T.N.G. Trinh, Arthur Corstanje, Tobias Winchen, Pim Schellart, Brian Hare, Satyendra Thoudam, J. P. Rachen, Stijn Buitink, Katie Mulrey, S. ter Veen, Jörg R. Hörandel, Laura Rossetto, Anna Nelles, Olaf Scholten, Pragati Mitra, Antonio Bonardi, Astronomy and Astrophysics Research Group, Physics, and Faculty of Sciences and Bioengineering Sciences

Subjects
Physics, 010308 nuclear & particles physics, QC1-999, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, LOFAR, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Signal chain, Frequency spectrum, law.invention, Telescope, Air shower, law, 0103 physical sciences, Range (statistics), Calibration, 010306 general physics, Energy (signal processing), Remote sensing
Abstract

The LOw-Frequency ARray (LOFAR) telescope measures radio emission from air showers. In order to interpret the data, an absolute, frequency dependent calibration is required. Due to a growing need for a better understanding of the measured frequency spectrum, we revisit the calibration of the LOFAR antennas in the range of 30—80 MHz. Using the galactic radio emission and a detailed model of the LOFAR signal chain, we find a calibration that provides an absolute energy scale and allows us to study frequency dependent features in measured air shower signals.

Published
2019

2. The association of a J-burst with a solar jet

Author

Helmut O. Rucker, Rebecca McFadden, B. Ciardi, J. M. Anderson, H. Munk, J. W. Broderick, O. Wucknitz, H. Paas, E. Juette, W. Reich, Heino Falcke, Matthias Hoeft, Hamish A. S. Reid, Oleg Smirnov, L. Cerrigone, A. G. Polatidis, Philip Best, Emanuela Orrú, Matthias Steinmetz, J. Magdalenic, D. D. Mulcahy, Gottfried Mann, C. Vocks, P. Zarka, V. N. Pandey, Ashish Asgekar, Mark J. Bentum, Gerard H. Kuper, A. Nelles, Annalisa Bonafede, M. Iacobelli, Diana E. Morosan, Dominik J. Schwarz, M. Pandey-Pommier, M. C. Toribio, R. C. Vermeulen, Jochen Eislöffel, Jean-Mathias Griessmeier, M. Tagger, S. ter Veen, A. W. Gunst, S. Duscha, Mario M. Bisi, R. Blaauw, R. J. van Weeren, D. McKay-Bukowski, I. M. Avruch, Peter T. Gallagher, John McKean, Martin Bell, E. de Geus, M. A. Garrett, Richard Fallows, Frank Breitling, Bo Thidé, J. Sluman, Roberto Pizzo, Marcus Brüggen, Satyendra Thoudam, Astronomy, Kapteyn Astronomical Institute, Trinity College Dublin, Netherlands Institute for Radio Astronomy (ASTRON), SUPA School of Physics and Astronomy [Glasgow], University of Glasgow, Leibniz-Institut für Astrophysik Potsdam (AIP), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Royal Observatory of Belgium [Brussels] (ROB), Austrian Academy of Sciences (OeAW), Swedish Institute of Space Physics [Uppsala] (IRF), GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Royal Observatory Edinburgh (ROE), University of Edinburgh, Jacobs University [Bremen], Universität Hamburg (UHH), Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Thüringer Landessternwarte Tautenburg (TLS), 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), Unité Scientifique de la Station de Nançay (USN), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Leiden Observatory [Leiden], Universiteit Leiden, Ruhr-Universität Bochum [Bochum], University of Oulu, Radboud University [Nijmegen], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), Universität Bielefeld, Rhodes University, Grahamstown, Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures (DSMZ), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-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 Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), Universiteit Leiden [Leiden], Radboud university [Nijmegen], École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and Harvard University [Cambridge]-Smithsonian Institution

Subjects
corona [Sun], 010504 meteorology & atmospheric sciences, Astronomy, particle emission [Sun], Astrophysics, 01 natural sciences, ELECTRON-BEAMS, CORONA, Sun: magnetic, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), 010303 astronomy & astrophysics, Sun: magnetic fields, fields, Physics, Jet (fluid), Solar flare, Sun: radio radiation, Astrophysics::Instrumentation and Methods for Astrophysics, FLARE, Astrophysics - Solar and Stellar Astrophysics, magnetic fields [Sun], Physical Sciences, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, FLUX, DYNAMICS-OBSERVATORY SDO, Field line, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy & Astrophysics, ACCELERATION, Computer Science::Digital Libraries, III BURSTS, Sun: particle emission, 0103 physical sciences, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Science & Technology, radio radiation [Sun], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Sun: corona, Northern Hemisphere, Astronomy and Astrophysics, Magnetic reconnection, LOFAR, Physics::History of Physics, X-RAY JETS, 13. Climate action, Space and Planetary Science, Extreme ultraviolet, RADIO-EMISSION
Abstract

Context. The Sun is an active star that produces large-scale energetic events such as solar flares and coronal mass ejections and numerous smaller-scale events such as solar jets. These events are often associated with accelerated particles that can cause emission at radio wavelengths. The reconfiguration of the solar magnetic field in the corona is believed to be the cause of the majority of solar energetic events and accelerated particles. Aims. Here, we investigate a bright J-burst that was associated with a solar jet and the possible emission mechanism causing these two phenomena. Methods. We used data from the Solar Dynamics Observatory (SDO) to observe a solar jet, and radio data from the Low Frequency Array (LOFAR) and the Nan\c{c}ay Radioheliograph (NRH) to observe a J-burst over a broad frequency range (33-173 MHz) on 9 July 2013 at ~11:06 UT. Results. The J-burst showed fundamental and harmonic components and it was associated with a solar jet observed at extreme ultraviolet wavelengths with SDO. The solar jet occurred at a time and location coincident with the radio burst, in the northern hemisphere, and not inside a group of complex active regions in the southern hemisphere. The jet occurred in the negative polarity region of an area of bipolar plage. Newly emerged positive flux in this region appeared to be the trigger of the jet. Conclusions. Magnetic reconnection between the overlying coronal field lines and the newly emerged positive field lines is most likely the cause of the solar jet. Radio imaging provides a clear association between the jet and the J-burst which shows the path of the accelerated electrons., Comment: 11 pages, 8 figures

Published
2017
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3. Constraints on the low frequency spectrum of FRB 121102

Author

Heino Falcke, Jörg P. Rachen, S. ter Veen, Laura Spitler, Michael Kramer, and Leon Houben

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Physics, education.field_of_study, Spectral index, 010308 nuclear & particles physics, Astronomy, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, LOFAR, Low frequency, 01 natural sciences, Power law, Flattening, Spectral line, Radio telescope, Space and Planetary Science, 0103 physical sciences, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Astrophysics - High Energy Astrophysical Phenomena, education, 010303 astronomy & astrophysics
Abstract

While repeating fast radio bursts (FRBs) remain scarce in number, they provide a unique opportunity for follow-up observations that enhance our knowledge of their sources and potentially of the FRB population as a whole. Attaining more burst spectra could lead to a better understanding of the origin of these bright, millisecond-duration radio pulses. We therefore performed $\sim$20 hr of simultaneous observations on FRB 121102 with the Effelsberg 100-m radio telescope and the Low Frequency Array (LOFAR) to constrain the spectral behaviour of bursts from FRB 121102 at 1.4 GHz and 150 MHz. This campaign resulted in the detection of nine new bursts at 1.4 GHz but no simultaneous detections with LOFAR. Assuming that the ratio of the fluence at two frequencies scales as a power law, we placed a lower limit of $��$ > -1.2 $\pm$ 0.4 on the spectral index for the fluence of the instantaneous broad band emission of FRB 121102. For the derivation of this limit, a realistic fluence detection threshold for LOFAR was determined empirically assuming a burst would be scattered as predicted by the NE2001 model. A significant variation was observed in the burst repeat rate R at L-band. During observations in September 2016, nine bursts were detected, giving R = 1.1 $\pm$ 0.4 hr$^{-1}$, while in November no bursts were detected, yielding R < 0.3 hr$^{-1}$ (95% confidence limit). This variation is consistent with earlier seen episodic emission of FRB 121102. In a blind and targeted search, no bursts were found with LOFAR at 150 MHz, resulting in a repeat rate limit of R < 0.16 hr$^{-1}$ (95% confidence limit). Burst repeat rate ratios of FRB 121102 at 3, 2, 1.4, and 0.15 GHz are consistent within the uncertainties with a flattening of its spectrum below 1 GHz., 8 pages, 2 tables, 1 figure

Published
2019
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4. A new parametrization for the radio emission of air showers applied to LOFAR data

Author

Brian Hare, Arthur Corstanje, Antonio Bonardi, Pim Schellart, Pragati Mitra, Tobias Winchen, Jörg R. Hörandel, Heino Falcke, J. P. Rachen, T. N. G. Trinh, I. Plaisier, Satyendra Thoudam, S. ter Veen, Laura Rossetto, Anna Nelles, Stijn Buitink, Katie Mulrey, Olaf Scholten, S. J. De Jong, Astronomy and Astrophysics Research Group, Physics, and Faculty of Sciences and Bioengineering Sciences

Subjects
Physics, QC1-999, Astronomy, Computer Science::Information Retrieval, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, LOFAR, Mass composition, Computational physics, Earth's magnetic field, Primary (astronomy), Energy density, High Energy Physics, Parametrization, Energy (signal processing)
Abstract

The energy and mass composition of cosmic rays influence how the energy density of the radio emission of air showers is distributed on the ground. A precise description of the radio profiles can, therefore, be used to reconstruct the properties of the primary cosmic rays. Here, such a description is presented, using a separate treatment of the two radio-emission mechanisms, the geomagnetic effect and the charge excess effect. The model is parametrized as a function that depends only on the shower parameters, allowing for a precise reconstruction of the properties of the primary cosmic rays. This model is applied to cosmic-ray events measured with LOFAR and it is capable of reconstructing the properties of air showers correctly.

Published
2019
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