Detecting Pulsars with Interstellar Scintillation in Variance Images

Abstract

Pulsars are the only cosmic radio sources known to be sufficiently compact to show diffractive interstellar scintillations. Images of the variance of radio signals in both time and frequency can be used to detect pulsars in large-scale continuum surveys using the next generation of synthesis radio telescopes. This technique allows a search over the full field of view while avoiding the need for expensive pixel-by-pixel high time resolution searches. We investigate the sensitivity of detecting pulsars in variance images. We show that variance images are most sensitive to pulsars whose scintillation time-scales and bandwidths are close to the subintegration time and channel bandwidth. Therefore, in order to maximise the detection of pulsars for a given radio continuum survey, it is essential to retain a high time and frequency resolution, allowing us to make variance images sensitive to pulsars with different scintillation properties. We demonstrate the technique with Murchision Widefield Array data and show that variance images can indeed lead to the detection of pulsars by distinguishing them from other radio sources.

8 papes, 9 figures, accepted for publication in MNRAS

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• Searching For Pulsars Associated With the Fermi GeV Excess
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• Serendipitous Discovery of PSR J1431-6328 as a Highly-Polarized Point Source with the Australian SKA Pathfinder
• Prospects for Discovering Pulsars in Future Continuum Surveys Using Variance Imaging
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• Revisiting Pulsar Velocities Using Gaia Data Release 2
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• SPARKESX: Single-dish PARKES data sets for finding the uneXpected -- A data challenge
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