Journal article
THE LOW-FREQUENCY CHARACTERISTICS OF PSR J0437-4715 OBSERVED WITH THE MURCHISON WIDE-FIELD ARRAY
NDR Bhat, SM Ord, SE Tremblay, SJ Tingay, AA Deshpande, W van Straten, S Oronsaye, G Bernardi, JD Bowman, F Briggs, RJ Cappallo, BE Corey, D Emrich, R Goeke, LJ Greenhill, BJ Hazelton, JN Hewitt, M Johnston-Hollitt, DL Kaplan, JC Kasper Show all
ASTROPHYSICAL JOURNAL LETTERS | IOP PUBLISHING LTD | Published : 2014
Abstract
We report on the detection of the millisecond pulsar PSR J0437-4715 with the Murchison Wide-field Array (MWA) at a frequency of 192 MHz. Our observations show rapid modulations of pulse intensity in time and frequency that arise from diffractive scintillation effects in the interstellar medium (ISM), as well as prominent drifts of intensity maxima in the time-frequency plane that arise from refractive effects. Our analysis suggests that the scattering screen is located at a distance of ∼80-120 pc from the Sun, in disagreement with a recent claim that the screen is closer (∼10 pc). Comparisons with higher frequency data from Parkes reveal a dramatic evolution of the pulse profile with frequen..
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Grants
Awarded by U.S. National Science Foundation
Awarded by Australian Research Council (LIEF)
Awarded by U.S. Air Force Office of Scientific Research
Awarded by Centre for All-sky Astrophysics (an ARC Centre of Excellence)
Awarded by Victoria University of Wellington via from the New Zealand Ministry of Economic Development
Funding Acknowledgements
We thank the referee for several insightful comments that helped improve the Letter. This scientific work makes use of the Murchison Radio-astronomy Observatory, operated by CSIRO. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. N.D.R.B. is supported by a Curtin Research Fellowship. We thank Matthew Bailes and Bryan Gaensler for useful comments, and Dick Manchester and Lawrence Toomey for help with access to the 430 MHz archival data. Support for the MWA comes from the U.S. National Science Foundation (grants AST-0457585, PHY-0835713, CAREER-0847753, and AST-0908884), the Australian Research Council (LIEF grants LE0775621 and LE0882938), the U.S. Air Force Office of Scientific Research (grant FA9550-0510247), and the Centre for All-sky Astrophysics (an ARC Centre of Excellence funded by grant CE110001020). Support is also provided by the Smithsonian Astrophysical Observatory, the MIT School of Science, the Raman Research Institute, the Australian National University, and the Victoria University of Wellington (via grant MED-E1799 from the New Zealand Ministry of Economic Development and an IBM Shared University Research Grant). The Australian Federal government provides additional support via CSIRO, National Collaborative Research Infrastructure Strategy, Education Investment Fund, and the Australia India Strategic Research Fund, and Astronomy Australia Limited, under contract to Curtin University. We acknowledge the iVEC Petabyte Data Store, the Initiative in Innovative Computing and the CUDA Center for Excellence sponsored by NVIDIA at Harvard University, and the International Centre for Radio Astronomy Research, a joint venture of Curtin University and The University of Western Australia, funded by the Western Australian State government.