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Accepted manuscript

Evolutionary Map of the Universe: A pilot survey to detect high Galactic latitude pulsars in variance images with ASKAP

Published online by Cambridge University Press:  04 May 2026

A. Ahmad Open the ORCID record for A. Ahmad [Opens in a new window] ,
S. Dai Open the ORCID record for S. Dai [Opens in a new window] ,
E. Lenc Open the ORCID record for E. Lenc [Opens in a new window] ,
M. D. Filipović Open the ORCID record for M. D. Filipović [Opens in a new window] ,
B. S. Koribalski Open the ORCID record for B. S. Koribalski [Opens in a new window] ,
S. Johnston Open the ORCID record for S. Johnston [Opens in a new window] ,
G. Hobbs Open the ORCID record for G. Hobbs [Opens in a new window] ,
S.W. Duchesne Open the ORCID record for S.W. Duchesne [Opens in a new window] ,
S. Lazarević Open the ORCID record for S. Lazarević [Opens in a new window]  and
L. Toomey Open the ORCID record for L. Toomey [Opens in a new window]
...Show all authors
A. Ahmad*
Affiliation:
School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
S. Dai
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
E. Lenc
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia
M. D. Filipović
Affiliation:
School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
B. S. Koribalski
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
S. Johnston
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia
G. Hobbs
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia
S.W. Duchesne
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, PO Box 1130, Bentley WA 6102, Australia
S. Lazarević
Affiliation:
School of Science, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia Astronomical Observatory, Volgina 7, 11060 Belgrade, Serbia
L. Toomey
Affiliation:
Australia Telescope National Facility, CSIRO, Space and Astronomy, P.O. Box 76, Epping, NSW 1710, Australia
N. D. R. Bhat
Affiliation:
International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102, Australia
D. A. Leahy
Affiliation:
Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada
A. M. Hopkins
Affiliation:
School of Mathematical and Physical Sciences, 12 Wally’s Walk, Macquarie University, NSW 2109, Australia Macquarie University Astrophysics and Space Technologies Research Centre, Sydney, NSW, Australia
T. Zafar
Affiliation:
School of Mathematical and Physical Sciences, 12 Wally’s Walk, Macquarie University, NSW 2109, Australia Macquarie University Astrophysics and Space Technologies Research Centre, Sydney, NSW, Australia
S. F. Rahman
Affiliation:
Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, Pakistan
*
Author for correspondence: A. Ahmad, Email: 22031320@student.westernsydney.edu.au.
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Abstract

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It has been proposed that radio pulsars can be distinguished from other point-like radio sources in continuum images by their unique interstellar scintillation signatures. Using data from the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe (EMU) survey, we conducted a pilot survey of radio pulsars at high Galactic latitude regions via the variance imaging method. Out of approximately 59,800 compact radio sources detected in a ∼480 square degree survey area, we identified 21 highly variable sources. Among them, 10 are known pulsars, 2 are known radio stars, 1 is a long period transient, 3 are radio star candidates, and the remaining 5 are pulsar candidates. Notably, we discovered two strongly scintillating pulsars: one with a period of 85.707 ms and a dispersion measure (DM) of 19.4 cm–3 pc, and another with a period of 5.492 ms and a DM of 29.5 cm–3 pc. In addition, a third pulsar was discovered in the variance images, with a period of 14.828 ms and a DM of 39.0 cm–3 pc. This source shows a steep radio spectrum and a high degree of circular polarisation. These results underscore the strong potential of variance imaging for pulsar detection in full EMU and future radio continuum surveys planned with Square Kilometre Array (SKA).

Keywords

pulsars: generaltechniques: interferometricISM: Interstellar scintillationsurveys: radio continuum

Information

Type
Research Article
Information
Publications of the Astronomical Society of Australia , Accepted manuscript , pp. 1 - 18
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of Astronomical Society of Australia