@article{0fe11a1bbcea43779cf58d5e648d6df9,
title = "Calibration of the LOFAR low-band antennas using the Galaxy and a model of the signal chain",
abstract = "The LOw-Frequency ARray (LOFAR) is used to make precise measurements of radio emission from extensive air showers, yielding information about the primary cosmic ray. Interpreting the measured data requires an absolute and frequency-dependent calibration of the LOFAR system response. This is particularly important for spectral analyses, because the shape of the detected signal holds information about the shower development. We revisit the calibration of the LOFAR antennas in the range of 30–80 MHz. Using the Galactic emission and a detailed model of the LOFAR signal chain, we find an improved calibration that provides an absolute energy scale and allows for the study of frequency dependent features in measured signals. With the new calibration, systematic uncertainties of 13% are reached, and comparisons of the spectral shape of calibrated data with simulations show promising agreement.",
keywords = "Air showers, Calibration, Radio antenna array",
author = "K. Mulrey and A. Bonardi and S. Buitink and A. Corstanje and H. Falcke and Hare, {B. M.} and H{\"o}randel, {J. R.} and T. Huege and P. Mitra and A. Nelles and Rachen, {J. P.} and L. Rossetto and P. Schellart and O. Scholten and {ter Veen}, S. and S. Thoudam and Trinh, {T. N.G.} and T. Winchen",
note = "Funding Information: The authors would like to thank Frank Schr{\"o}der and Dmitriy Kostunin for their help comparing LOFAR results with Tunka–Rex results, and for the preparation of Fig. 8 . The LOFAR cosmic-ray key science project acknowledges funding from an Advanced Grant of the European Research Council (FP/2007-2013) / ERC grant agreement no. 227610 . The project has also received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (grant agreement no. 640130 ). We furthermore acknowledge financial support from FOM , (FOM-project 12PR304 ). TW is supported by DFG grant WI 4946/1-1 . AN is supported by the DFG grant NE 2031/2-1 . LOFAR, the Low Frequency Array designed and constructed by ASTRON, has facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the International LOFAR Telescope foundation under a joint scientific policy. Funding Information: The authors would like to thank Frank Schr{\"o}der and Dmitriy Kostunin for their help comparing LOFAR results with Tunka–Rex results, and for the preparation of Fig. 8. The LOFAR cosmic-ray key science project acknowledges funding from an Advanced Grant of the European Research Council (FP/2007-2013) / ERC grant agreement no. 227610. The project has also received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (grant agreement no. 640130). We furthermore acknowledge financial support from FOM, (FOM-project 12PR304). TW is supported by DFG grant WI 4946/1-1. AN is supported by the DFG grant NE 2031/2-1. LOFAR, the Low Frequency Array designed and constructed by ASTRON, has facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the International LOFAR Telescope foundation under a joint scientific policy. Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",
year = "2019",
month = sep,
doi = "10.1016/j.astropartphys.2019.03.004",
language = "British English",
volume = "111",
pages = "1--11",
journal = "Astroparticle Physics",
issn = "0927-6505",
publisher = "Elsevier",
}