A LOFAR census of non-recycled pulsars: average profiles, dispersion measures, flux densities, and spectra^⋆

¹ Department of Astrophysics/IMAPP, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands
² Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
e-mail: A.Bilous@uva.nl
³ ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands
⁴ Astro Space Centre, Lebedev Physical Institute, Russian Academy of Sciences, Profsoyuznaya Str. 84/32, 117997 Moscow, Russia
⁵ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁶ Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK
⁷ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Mail H30, PO Box 218, VIC 3122, Australia
⁸ ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), The University of Sydney, 44 Rosehill Street, 2016 Redfern, Australia
⁹ SKA Organisation, Jodrell Bank Observatory, Lower Withington, Macclesfield, Cheshire, SK11 9DL, UK
¹⁰ Pushchino Radio Astronomy Observatory, 142290 Pushchino, Moscow region, Russia
¹¹ School of Physics and Astronomy, University of Southampton, SO17 1BJ, UK
¹² Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
¹³ Department of Physics & Astronomy, University of the Western Cape, Private Bag X17, 7535 Bellville, South Africa
¹⁴ Department of Physics and Electronics, Rhodes University, PO Box 94, 6140 Grahamstown, South Africa
¹⁵ Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
¹⁶ LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
¹⁷ Station de Radioastronomie de Nançay, Observatoire de Paris, PSL Research University, CNRS, Univ. Orléans, OSUC, Nançay 18330, France
¹⁸ LPC2E – Université d’Orléans/CNRS, 45071 Orléans Cedex 2, France
¹⁹ CSIRO Astronomy and Space Science, PO Box 76, 1710 Epping, Australia
²⁰ Thüringer Landessternwarte, Sternwarte 5, 07778 Tautenburg, Germany

Received: 5 November 2015
Accepted: 30 March 2016

Abstract

We present first results from a LOFAR census of non-recycled pulsars. The census includes almost all such pulsars known (194 sources) at declinations Dec > 8° and Galactic latitudes |Gb| > 3°, regardless of their expected flux densities and scattering times. Each pulsar was observed for ≥20 min in the contiguous frequency range of 110–188 MHz. Full-Stokes data were recorded. We present the dispersion measures, flux densities, and calibrated total intensity profiles for the 158 pulsars detected in the sample. The median uncertainty in census dispersion measures (1.5 × 10^-3 pc cm^-3) is ten times smaller, on average, than in the ATNF pulsar catalogue. We combined census flux densities with those in the literature and fitted the resulting broadband spectra with single or broken power-law functions. For 48 census pulsars such fits are being published for the first time. Typically, thechoice between single and broken power-laws, as well as the location of the spectral break, were highly influenced by the spectral coverage of the available flux density measurements. In particular, the inclusion of measurements below 100 MHz appears essential for investigating the low-frequency turnover in the spectra for most of the census pulsars. For several pulsars, we compared the spectral indices from different works and found the typical spread of values to be within 0.5–1.5, suggesting a prevailing underestimation of spectral index errors in the literature. The census observations yielded some unexpected individual source results, as we describe in the paper. Lastly, we will provide this unique sample of wide-band, low-frequency pulse profiles via the European Pulsar Network Database.