Scintillation of PSR B1508+55 – the view from a 10 000-km baseline
Abstract
We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550–750 MHz of the scintillation of PSR B1508+55, resulting in an ∼10 000-km baseline. This regime of measurement lies between the shorter few 100- to 1000-km baselines of earlier multistation observations and the much longer earth–space baselines. We measure a scintillation cross-correlation coefficient of 0.22, offset from zero time lag due to a ∼45-s traversal time of the scintillation pattern. The scintillation time of 135 s is 3× longer, ruling out isotropic as well as strictly one-dimensional scattering. Hence, the low cross-correlation coefficient is indicative of highly anisotropic but two-dimensional scattering. The common scintillation detected on the baseline is confined to low delays of ≲1μs, suggesting that this correlation may not be associated with the parabolic scintillation arc detected at the GMRT. Detection of pulsed echoes and their direct imaging with the Low-Frequency Array (LOFAR) by a different group enable them to measure a distance of 125 pc to the screen causing these echoes. These previous measurements, alongside our observations, lead us to propose that there are at least two scattering screens: the closer 125-pc screen causing the scintillation arc detected at GMRT, and a screen further beyond causing the scintillation detected on the GMRT-ARO baseline. We advance the hypothesis that the 125-pc screen partially resolves the speckle images on the screen beyond leading to loss of coherence in the scintillation dynamic spectrum to explain the low cross-correlation coefficient.
Additional Information
© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 July 2. Received 2021 June 6; in original form 2020 October 19. Published: 19 July 2021. We thank the anonymous reviewer whose critical comments have helped greatly enhance the clarity of the contents and the presentation. We dedicate this paper to the memory of Govind Swarup and Jean-Pièrre Macquart. VRM thanks Olaf Wucknitz, Stefan Osłowski, and J-P Macquart for several insightful discussions. VRM was supported by a SOSCIP Consortium Postdoctoral Fellowship. VRM acknowledges support of the Department of Atomic Energy, Government of India, under project no. 12-R&D-TFR-5.02-0700. We thank the staff of the GMRT that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. We thank the research collaboration and funding support of Thoth Technology, Inc., which owns and operates ARO and contributed significantly to this research. We also acknowledge the Ontario Research Fund – Research Excellence program (ORF-RE) and NSERC. Computations were performed on the Niagara supercomputer at the SciNet HPC Consortium. SciNet is funded by: the Canada Foundation for Innovation; the Government of Ontario; Ontario Research Fund – Research Excellence; and the University of Toronto. Data Availability: The data underlying this article will be shared on reasonable request to the corresponding author.Attached Files
Published - stab1970.pdf
Accepted Version - 2010.09723.pdf
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Additional details
- Eprint ID
- 111810
- Resolver ID
- CaltechAUTHORS:20211109-224612699
- SOSCIP Consortium Postdoctoral Fellowship
- 12-R&D-TFR-5.02-0700
- Department of Atomic Energy (India)
- Thoth Technology Inc.
- Ontario Research Fund-Research Excellence
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Canada Foundation for Innovation
- University of Toronto
- Created
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2021-11-11Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field