期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 471, 期 3, 页码 3563-3576出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stx1777
关键词
scattering; pulsars: general; H II regions; ISM: supernova remnants; Galaxy: centre
资金
- Sofja Kovalevskaja Award from the Alexander von Humboldt Foundation of Germany
- National Science Foundation [NSF PHY-1125915]
- European Research Council for the ERC Synergy Grant Black-HoleCam [610058]
- ERC Starting Grant BEACON [279702]
- Max Planck Society
- NASA
- Commonwealth Government
- Division Of Physics
- Direct For Mathematical & Physical Scien [1430284] Funding Source: National Science Foundation
- Science and Technology Facilities Council [ST/P000649/1] Funding Source: researchfish
- European Research Council (ERC) [279702] Funding Source: European Research Council (ERC)
- STFC [ST/P000649/1] Funding Source: UKRI
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 (Delta l < 20 degrees). 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 less than or similar to 0 degrees.2. A second scattering component closer to (Delta < 2 kpc) or even (tentatively) within (Delta < 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 similar or equal to 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 H II 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 H II regions should contribute greater than or similar to 25 per cent of the total dispersion measure (DM) towards these pulsars, and calculate reduced DM distances. Those distances for other pulsars lying behind H II regions may be similarly overestimated.
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