Radio emission evolution, polarimetry and multifrequency single pulse analysis of the radio magnetar PSR J1622−4950

Authors

  • L. Levin,

    Corresponding author
    1. Swinburne University of Technology, Centre for Astrophysics and Supercomputing, Mail H30, PO Box 218, VIC 3122, Australia
    2. Australia Telescope National Facility, CSIRO Astronomy & Space Science, PO Box 76, Epping, NSW 1710, Australia
      E-mail: llevin@astro.swin.edu.au
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  • M. Bailes,

    1. Swinburne University of Technology, Centre for Astrophysics and Supercomputing, Mail H30, PO Box 218, VIC 3122, Australia
    2. ARC Centre for All-Sky Astronomy (CAASTRO), School of Physics A28, The University of Sydney, NSW 2006, Australia
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  • S. D. Bates,

    1. Department of Physics, West Virginia University, 210E Hodges Hall, Morgantown, WV 26506, USA
    2. University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester M13 9PL
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  • N. D. R. Bhat,

    1. Swinburne University of Technology, Centre for Astrophysics and Supercomputing, Mail H30, PO Box 218, VIC 3122, Australia
    2. ARC Centre for All-Sky Astronomy (CAASTRO), School of Physics A28, The University of Sydney, NSW 2006, Australia
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  • M. Burgay,

    1. INAF-Osservatorio Astronomico di Cagliari, località Poggio dei Pini, strada 54, I-09012 Capoterra, Italy
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  • S. Burke-Spolaor,

    1. Australia Telescope National Facility, CSIRO Astronomy & Space Science, PO Box 76, Epping, NSW 1710, Australia
    2. NASA Jet Propulsion Laboratory, M/S 138-307, Pasadena, CA 91106, USA
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  • N. D’Amico,

    1. INAF-Osservatorio Astronomico di Cagliari, località Poggio dei Pini, strada 54, I-09012 Capoterra, Italy
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  • S. Johnston,

    1. Australia Telescope National Facility, CSIRO Astronomy & Space Science, PO Box 76, Epping, NSW 1710, Australia
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  • M. J. Keith,

    1. Australia Telescope National Facility, CSIRO Astronomy & Space Science, PO Box 76, Epping, NSW 1710, Australia
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  • M. Kramer,

    1. Max Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
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  • S. Milia,

    1. INAF-Osservatorio Astronomico di Cagliari, località Poggio dei Pini, strada 54, I-09012 Capoterra, Italy
    2. Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria, 09042 Monserrato (CA), Italy
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  • A. Possenti,

    1. INAF-Osservatorio Astronomico di Cagliari, località Poggio dei Pini, strada 54, I-09012 Capoterra, Italy
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  • B. Stappers,

    1. University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester M13 9PL
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  • W. van Straten

    1. Swinburne University of Technology, Centre for Astrophysics and Supercomputing, Mail H30, PO Box 218, VIC 3122, Australia
    2. ARC Centre for All-Sky Astronomy (CAASTRO), School of Physics A28, The University of Sydney, NSW 2006, Australia
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E-mail: llevin@astro.swin.edu.au

ABSTRACT

Here we report on observations of the radio magnetar PSR J1622−4950 at frequencies from 1.4 to 17 GHz. We show that although its flux density is varying up to a factor of ∼10 within a few days, it has on average decreased by a factor of 2 over the last 700 days. At the same time, timing analysis indicates a trend of decreasing spin-down rate over our entire data set, again of about a factor of 2 over 700 days, but also an erratic variability in the spin-down rate within this time span. Integrated pulse profiles are often close to 100 per cent linearly polarized, but large variations in both the profile shape and fractional polarization are regularly observed. Furthermore, the behaviour of the position angle of the linear polarization is very complex – offsets in both the absolute position angle and the phase of the position angle sweep are often seen and the occasional presence of orthogonal mode jumps further complicates the picture. However, model fitting indicates that the magnetic and rotation axes are close to aligned. Finally, a single pulse analysis has been carried out at four observing frequencies, demonstrating that the wide pulse profile is built up of narrow spikes of emission, with widths that scale inversely with observing frequency. All three of the known radio magnetars seem to have similar characteristics, with highly polarized emission, time-variable flux density and pulse profiles, and with spectral indices close to zero.

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