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Paper: Interstellar Scattering in the Galactic Anticenter
Volume: 144, Radio Emission from Galactic and Extragalactic Compact Sources, IAU Colloquium 164
Page: 329
Authors: Lazio, T. J. W.; Cordes, J. M.
Abstract: Interstellar scattering dictates the limiting resolution for many pulsars and OH masers and some extragalactic sources, a limit made more important by the advent of space-based VLBI. Scattering observations have been biased toward the inner Galaxy, leaving largely unconstrained basic parameters such as the scattering medium's extent in the outer Galaxy. Ionized gas at ~50 kpc is suggested by the appearance of \Hi\ in nearby galaxies and models of low-redshift quasar absorption systems. We combine multiwavelength, VLBA observations of twelve extragalactic sources with previous scattering measurements of extragalactic sources and pulsars in the anticenter and constrain the radial extent of the scattering medium to 20 kpc, comparable to that of massive star formation. The \Hii\ disk does not display significant flaring or warping, though this conclusion may reflect the coarse sampling.
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