Locating the intense interstellar scattering towards the inner Galaxy

J. Dexter, A. Deller, G. C. Bower, P. Demorest, M. Kramer, B. W. Stappers, A. G. Lyne, M. Kerr, L. G. Spitler, Dimitrios Psaltis, M. Johnson, R. Narayan

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We use VLBA+VLA observations to measure the sizes of the scatter-broadened images of six of the most heavily scattered known pulsars: three within the Galactic Centre (GC) and three elsewhere in the inner Galactic plane (Δl < 20°). By combining the measured sizes with temporal pulse broadening data from the literature and using the thin-screen approximation, we locate the scattering medium along the line of sight to these six pulsars. At least two scattering screens are needed to explain the observations of the GC sample. We show that the screen inferred by previous observations of SGR J1745-2900 and Sgr A*, which must be located far from the GC, falls off in strength on scales ≲0. ° 2. A second scattering component closer to (Δ < 2 kpc) or even (tentatively) within (Δ < 700 pc) the GC produces most or all of the temporal broadening observed in the other GC pulsars. Outside the GC, the scattering locations for all three pulsars are ≃2 kpc from Earth, consistent with the distance of the Carina-Sagittarius or Scutum spiral arm. For each object the 3D scattering origin coincides with a known HII region (and in one case also a supernova remnant), suggesting that such objects preferentially cause the intense interstellar scattering seen towards the Galactic plane. We show that the HII regions should contribute ≳25 per cent of the total dispersion measure (DM) towards these pulsars, and calculate reduced DM distances. Those distances for other pulsars lying behind HII regions may be similarly overestimated.

Original languageEnglish (US)
Pages (from-to)3563-3576
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume471
Issue number3
DOIs
StatePublished - Jan 1 2017

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pulsars
scattering
galaxies
supernova remnants
line of sight
causes
pulses
approximation

Keywords

  • Galaxy: centre
  • ISM: supernova remnants
  • Pulsars: general -HII regions
  • Scattering

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Dexter, J., Deller, A., Bower, G. C., Demorest, P., Kramer, M., Stappers, B. W., ... Narayan, R. (2017). Locating the intense interstellar scattering towards the inner Galaxy. Monthly Notices of the Royal Astronomical Society, 471(3), 3563-3576. https://doi.org/10.1093/MNRAS/STX1777

Locating the intense interstellar scattering towards the inner Galaxy. / Dexter, J.; Deller, A.; Bower, G. C.; Demorest, P.; Kramer, M.; Stappers, B. W.; Lyne, A. G.; Kerr, M.; Spitler, L. G.; Psaltis, Dimitrios; Johnson, M.; Narayan, R.

In: Monthly Notices of the Royal Astronomical Society, Vol. 471, No. 3, 01.01.2017, p. 3563-3576.

Research output: Contribution to journalArticle

Dexter, J, Deller, A, Bower, GC, Demorest, P, Kramer, M, Stappers, BW, Lyne, AG, Kerr, M, Spitler, LG, Psaltis, D, Johnson, M & Narayan, R 2017, 'Locating the intense interstellar scattering towards the inner Galaxy', Monthly Notices of the Royal Astronomical Society, vol. 471, no. 3, pp. 3563-3576. https://doi.org/10.1093/MNRAS/STX1777
Dexter J, Deller A, Bower GC, Demorest P, Kramer M, Stappers BW et al. Locating the intense interstellar scattering towards the inner Galaxy. Monthly Notices of the Royal Astronomical Society. 2017 Jan 1;471(3):3563-3576. https://doi.org/10.1093/MNRAS/STX1777
Dexter, J. ; Deller, A. ; Bower, G. C. ; Demorest, P. ; Kramer, M. ; Stappers, B. W. ; Lyne, A. G. ; Kerr, M. ; Spitler, L. G. ; Psaltis, Dimitrios ; Johnson, M. ; Narayan, R. / Locating the intense interstellar scattering towards the inner Galaxy. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 471, No. 3. pp. 3563-3576.
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