Dual-frequency single-pulse study of PSR B0950+08

¹ ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands
e-mail: hanna.bilous@gmail.com
² LPC2E – Université d’Orléans/CNRS, 45071 Orléans Cedex 2, France
³ Station de Radioastronomie de Nançay, Observatoire de Paris, PSL Research University, CNRS, Univ. Orléans, OSUC, 18330 Nançay, France
⁴ National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903, USA
⁵ Institute of Physics, Eötvös Loránd University, Pázmány P. s. 1/A, 1117 Budapest, Hungary
⁶ Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
⁷ LESIA and USN, Observatoire de Paris, CNRS, PSL, SU/UP/UO, 92195 Meudon, France
⁸ Astro Space Center of Lebedev Physical Institute, Profsoyuznaya Str. 84/32, 117997 Moscow, Russia
⁹ Anton Pannekoek Institute, University of Amsterdam, Postbus 94249, 1090 GE Amsterdam, The Netherlands
¹⁰ National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, 411007 Maharashtra, India
¹¹ Cahill Center for Astronomy, California Institute of Technology, Pasadena, CA, USA
¹² Netherlands eScience Center, Science Park 140, 1098 XG Amsterdam, The Netherlands
¹³ Department of Physics, McGill University, 3600 rue University, Montréal, QC H3A 2T8, Canada
¹⁴ McGill Space Institute, McGill University, 3550 rue University, Montréal, QC H3A 2A7, Canada
¹⁵ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
¹⁶ Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 Saint George Street, Toronto, ON M5S 3H8, Canada
¹⁷ Dipartimento di Fisica “G. Occhialini”, Universitá degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
¹⁸ Laboratoire Univers et Théories, Observatoire de Paris, Université PSL, CNRS, Université de Paris, 92190 Meudon, France
¹⁹ Institute of Radio Astronomy of the National Academy of Sciences of Ukraine, 4, Mystetstv St., Kharkiv 61002, Ukraine
²⁰ AIM, CEA, CNRS, Université de Paris, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
²¹ Dept. of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden
²² University of Oslo Center for Information Technology, PO Box 1059 0316 Oslo, Norway

Received: 17 September 2021
Accepted: 4 November 2021

Abstract

PSR B0950+08 is a bright nonrecycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR) and 1.4 GHz (Westerbork Synthesis Radio Telescope), we review the properties of these single pulses. We conclude that they are more similar to ordinary pulses of radio emission than to a special kind of short and bright giant pulses, observed from only a handful of pulsars. We argue that a temporal variation of the properties of the interstellar medium along the line of sight to this nearby pulsar, namely the fluctuating size of the decorrelation bandwidth of diffractive scintillation makes an important contribution to the observed single-pulse fluence variability. We further present interesting structures in the low-frequency single-pulse spectra that resemble the “sad trombones” seen in fast radio bursts (FRBs); although for PSR B0950+08 the upward frequency drift is also routinely present. We explain these spectral features with radius-to-frequency mapping, similar to the model developed by Wang et al. (2019, ApJ, 876, L15) for FRBs. Finally, we speculate that μs-scale fluence variability of the general pulsar population remains poorly known, and that its further study may bring important clues about the nature of FRBs.