SIMULTANEOUS OBSERVATIONS of GIANT PULSES from the CRAB PULSAR, with the MURCHISON WIDEFIELD ARRAY and PARKES RADIO TELESCOPE: IMPLICATIONS for the GIANT PULSE EMISSION MECHANISM

S. I. Oronsaye, S. M. Ord, N. D R Bhat, S. E. Tremblay, S. J. McSweeney, S. J. Tingay, W. V. Van Straten, A. Jameson, G. Bernardi, Judd Bowman, F. Briggs, R. J. Cappallo, A. A. Deshpande, L. J. Greenhill, B. J. Hazelton, M. Johnston-Hollitt, D. L. Kaplan, C. J. Lonsdale, S. R. McWhirter, D. A. MitchellM. F. Morales, E. Morgan, D. Oberoi, T. Prabu, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, R. B. Wayth, R. L. Webster, A. Williams, C. L. Williams

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

We report on observations of giant pulses from the Crab pulsar performed simultaneously with the Parkes radio telescope and the incoherent combination of the Murchison Widefield Array (MWA) antenna tiles. The observations were performed over a duration of approximately one hour at a center frequency of 1382 MHz with 340 MHz bandwidth at Parkes, and at a center frequency of 193 MHz with 15 MHz bandwidth at the MWA. Our analysis has led to the detection of 55 giant pulses at the MWA and 2075 at Parkes above a threshold of 3.5σ and 6.5σ, respectively. We detected 51% of the MWA giant pulses at the Parkes radio telescope, with spectral indices in the range of -3.6 > α > -4.9 (Sv ∝ vα). We present a Monte Carlo analysis supporting the conjecture that the giant pulse emission in the Crab is intrinsically broadband, the less than 100% correlation being due to the relative sensitivities of the two instruments and the width of the spectral index distribution. Our observations are consistent with the hypothesis that the spectral index of giant pulses is drawn from normal distribution of standard deviation 0.6, but with a mean that displays an evolution with frequency from -3.00 at 1382 MHz, to -2.85 at 192 MHz.

Original languageEnglish (US)
Article number51
JournalAstrophysical Journal
Volume809
Issue number1
DOIs
StatePublished - Aug 10 2015

Keywords

  • ISM: individual objects (Crab Nebula)
  • ISM: structure
  • pulsars: general
  • pulsars: individual (Crab pulsar)
  • scattering

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Oronsaye, S. I., Ord, S. M., Bhat, N. D. R., Tremblay, S. E., McSweeney, S. J., Tingay, S. J., Van Straten, W. V., Jameson, A., Bernardi, G., Bowman, J., Briggs, F., Cappallo, R. J., Deshpande, A. A., Greenhill, L. J., Hazelton, B. J., Johnston-Hollitt, M., Kaplan, D. L., Lonsdale, C. J., McWhirter, S. R., ... Williams, C. L. (2015). SIMULTANEOUS OBSERVATIONS of GIANT PULSES from the CRAB PULSAR, with the MURCHISON WIDEFIELD ARRAY and PARKES RADIO TELESCOPE: IMPLICATIONS for the GIANT PULSE EMISSION MECHANISM. Astrophysical Journal, 809(1), [51]. https://doi.org/10.1088/0004-637X/809/1/51