Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR

Pilia M, Hessels JW, Stappers BW, Kondratiev VI, Kramer M, Van Leeuwen J, Weltevrede P, Lyne AG, Zagkouris K, Hassall TE, Bilous AV, Breton RP, Falcke H, Grießmeier JM, Keane E, Karastergiou A, Kuniyoshi M, Noutsos A, Osłowski S, Serylak M, Sobey C, Ter Veen S, Alexov A, Anderson J, Asgekar A, Avruch IM, Bell ME, Bentum MJ, Bernardi G, Bîrzan L, Bonafede A, Breitling F, Broderick JW, Brüggen M, Ciardi B, Corbel S, De Geus E, De Jong A, Deller A, Duscha S, Eislöffel J, Fallows RA, Fender R, Ferrari C, Frieswijk W, Garrett MA, Gunst AW, Hamaker JP, Heald G, Horneffer A, Jonker P, Juette E, Kuper G, Maat P, Mann G, Markoff S, McFadden R, McKay-Bukowski D, Miller-Jones JC, Nelles A, Paas H, Pandey-Pommier M, Pietka M, Pizzo R, Polatidis AG, Reich W, Röttgering H, Rowlinson A, Schwarz D, Smirnov O, Steinmetz M, Stewart A, Swinbank JD, Tagger M, Tang Y, Tasse C, Thoudam S, Toribio MC, Van Der Horst AJ, Vermeulen R, Vocks C, Van Weeren RJ, Wijers RA, Wijnands R, Wijnholds SJ, Wucknitz O, Zarka P (2016)

Publication Type: Journal article

Publication year: 2016

Journal

Book Volume: 586

Article Number: A92

DOI: 10.1051/0004-6361/201425196

Abstract

Context. LOFAR offers the unique capability of observing pulsars across the 10-240 MHz frequency range with a fractional bandwidth of roughly 50%. This spectral range is well suited for studying the frequency evolution of pulse profile morphology caused by both intrinsic and extrinsic effects such as changing emission altitude in the pulsar magnetosphere or scatter broadening by the interstellar medium, respectively. Aims. The magnitude of most of these effects increases rapidly towards low frequencies. LOFAR can thus address a number of open questions about the nature of radio pulsar emission and its propagation through the interstellar medium. Methods. We present the average pulse profiles of 100 pulsars observed in the two LOFAR frequency bands: high band (120-167 MHz, 100 profiles) and low band (15-62 MHz, 26 profiles). We compare them with Westerbork Synthesis Radio Telescope (WSRT) and Lovell Telescope observations at higher frequencies (350 and 1400 MHz) to study the profile evolution. The profiles were aligned in absolute phase by folding with a new set of timing solutions from the Lovell Telescope, which we present along with precise dispersion measures obtained with LOFAR. Results. We find that the profile evolution with decreasing radio frequency does not follow a specific trend; depending on the geometry of the pulsar, new components can enter into or be hidden from view. Nonetheless, in general our observations confirm the widening of pulsar profiles at low frequencies, as expected from radius-to-frequency mapping or birefringence theories.

Authors with CRIS profile

Involved external institutions

University of Manchester United Kingdom (GB) University of Oxford United Kingdom (GB) University of Southampton United Kingdom (GB) Radboud University Nijmegen Netherlands (NL) Astron Netherlands (NL) Space Telescope Science Institute (STScI) United States (USA) (US) Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum - GFZ Germany (DE) Max-Planck-Institut für Radioastronomie / Max Planck Institute for Radio Astronomy Germany (DE) Leiden University Netherlands (NL) Australia Telescope National Facility (ATNF) Australia (AU) Universität Bielefeld Germany (DE) Rhodes University South Africa (ZA) Leibniz Institute for Astrophysics Potsdam / Leibniz-Institut für Astrophysik Potsdam Germany (DE) Princeton University United States (USA) (US) University of Orléans / Université d'Orléans France (FR) University of Amsterdam Netherlands (NL) Swinburne University of Technology Australia (AU) Netherlands Institute for Space Research / Stichting Ruimteonderzoek Nederland (SRON) Netherlands (NL) Smithsonian Institution United States (USA) (US) Universität Hamburg (UHH) Germany (DE) Max-Planck-Institut für Astrophysik / Max Planck Institute for Astrophysics Germany (DE) Lagrange Laboratory France (FR) National Astronomical Observatory of Japan / 国立天文台(NAOJ) Japan (JP) University of the Western Cape (UWC) South Africa (ZA) Ruhr-Universität Bochum (RUB) Germany (DE) Sodankylä Geophysical Observatory Finland (FI) Curtin University Australia (AU) University of Groningen / Rijksuniversiteit Groningen Netherlands (NL) Centre de Recherche Astrophysique de Lyon (CRAL) France (FR) Laboratoire d'études Spatiales et d'Instrumentation en Astrophysique (LESIA) France (FR)

How to cite

APA:

Pilia, M., Hessels, J.W., Stappers, B.W., Kondratiev, V.I., Kramer, M., Van Leeuwen, J.,... Zarka, P. (2016). Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR. Astronomy & Astrophysics, 586. https://doi.org/10.1051/0004-6361/201425196

MLA:

Pilia, M., et al. "Wide-band, low-frequency pulse profiles of 100 radio pulsars with LOFAR." Astronomy & Astrophysics 586 (2016).

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