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Title: THE LOW-FREQUENCY CHARACTERISTICS OF PSR J0437–4715 OBSERVED WITH THE MURCHISON WIDE-FIELD ARRAY

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 frequency, with the outer conal emission becoming comparable in strength to that from the core and inner conal regions. As well as demonstrating the high time resolution science capabilities currently possible with the MWA, our observations underscore the potential to conduct low-frequency investigations of timing-array millisecond pulsars, which may lead to increased sensitivity in the detection of nanoHertz gravitational waves via the accurate characterization of ISM effects.
Authors:
; ; ; ; ;  [1] ;  [2] ; ;  [3] ;  [4] ;  [5] ; ;  [6] ; ;  [7] ; ;  [8] ;  [9] ;  [10] ;  [11] more »; « less
  1. International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102 (Australia)
  2. Raman Research Institute, Bangalore 560080 (India)
  3. ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Curtin University, Bentley, WA 6102 (Australia)
  4. Square Kilometre Array South Africa, 3rd Floor, The Park, Park Road, Pinelands, 7405 (South Africa)
  5. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
  6. MIT Haystack Observatory, Westford, MA 01886 (United States)
  7. Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
  8. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  9. Department of Physics, University of Washington, Seattle, WA 98195 (United States)
  10. School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand)
  11. Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States)
Publication Date:
OSTI Identifier:
22365284
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 791; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; DETECTION; GRAVITATIONAL WAVES; INTERFEROMETERS; INTERSTELLAR SPACE; MHZ RANGE; MODULATION; POTENTIALS; PULSARS; SCINTILLATIONS; SENSITIVITY; SUN; TIME RESOLUTION